Isaak Sirko (also known as Volk, Russian for "The Wolf") was a character on DEXTER. He was the leader of the Koshka Brotherhood, bases their operation in Kiev, Ukraine where Isaak lives. He is the owner of the chain of gentleman's clubs known as The Foxhole.
He was the Main Antagonist of Season Seven and the Seventh Main Antagonist in the series. He is the second antagonist to be from a foreign country (first being Lila West). Isaak has considerable fighting skills as he was able to kill three well armed men in a confined space with little damage to himself, making him one of the most dangerous main antagonists thus far. Like James Doakes and Jordan Chase, he was killed by someone else other than Dexter Morgan which is usually a rare occurrence.
Isaak is a dangerous yet sophisticated man with a calm demeanor. Shown to be well respected and feared among his subordinates, he is the leader of the Koshka Brotherhood. Despite his status as their highest ranking official, he does not avoid getting his own hands dirty when dealing with a "problem" and will carry out the deed himself despite being accompanied by Jurg Yeliashkevych, a friend and bodyguard. An example of this is when he murders Tony Rush, following an investigation of his own into the disappearance of one of his associates and lover Viktor Baskov. After determining that it was Tony who relayed Viktor's name to the Miami Metro Police Department, he stabbed him in the right eye with a nearby screwdriver, killing him in seconds.
Of note, Isaak appears to be very charismatic and will often talk to those around him in a lighthearted manner regardless of whether or not he has darker intents in mind. He'll crack a smile, even joke while speaking in a way that tries to put those in his crosshairs at ease.
Isaak is secretly gay, this was first revealed in "Argentina'' when Dexter follows him into a gay bar. In this episode, he also reveals the romantic relationship he shared with Viktor Baskov.
Isaak is a tall, handsome caucasian man in his late forties with greying hair. His attire consists mainly of expensive suits that were most likely imported from the Ukraine or Russia, and is always very professional.
Isaak is a lethally dangerous yet sophisticated man with a calm demeanor in most situations. Shown to be well respected and feared among his subordinates, he is the leader of the Koshka Brotherhood. Despite his status as their highest ranking official, he does not avoid getting his own hands dirty when dealing with a "problem" and will carry out the deed himself despite often being accompanied by Jurg Yeliashkevych. This can be seen clearly in his murder of Tony Rush, following an investigation of his own into the disappearance of one of his associates Viktor Baskov. After determining that it was Tony who relayed Viktor's name to the Miami Metro Police Department, he proceeded to stab him in the right eye with a nearby screwdriver...killing him in seconds.
Of an interesting note, unlike other main antagonists, like the self-serving Jordan Chase, Isaak actually cares for those that works under him, like Jurg and Viktor. The prime example was when he discovered of Victor's death Isaak became enraged and determined to avenge him and refused to speak ill of him. However, Isaak has shown to have cruelty towards some of his men, specifically having Alex Dubrozny kill himself to make the case around Mike Anderson's death go away, but this is not without honor, as Isaak promised to send his family money to set their lives for themselves if he killed himself, showing Isaak is a man who keeps his word, something he admitted to Dexter. His sense of honor is so great that he was willing to leave Dexter alone should Dexter rid two hitmen after Isaak, despite the deep animosity between them.
Of note, Isaak appears to be a rather eased individual and will often talk to those around him in a light-hearted manner regardless of whether or not he has darker intents in mind. He'll crack a smile, even joke while speaking in a way that tries to put those in his crosshairs at ease. Unlike most antagonists, Isaak has quite the sense of humor, going as far as to talk with Dexter on the phone and deliver Louis's message of him calling Dexter a "douchebag" with a small laugh. His sense of humor is also shown to be slightly twisted, as when he watched as Dexter described the crime scene at his apartment and how the perp died, Isaak jokingly said "my my, you couldn't have described it better yourself if you had been there".
With the Brotherhood, Isaak is very respected and feared by his men. However, not all of them respect him, as George Novikov has some level of respect for his boss, but is more than willing to betray him should he feel Isaak is not worthy, going as far as to send hitmen after him (an irony since this incident caused Isaak and Dexter to become closer to one another). With his body guard Jurg, Isaak respects him not just as a body guard, but as a friend, as Jurg has an immense respect and is fiercely loyal to Isaak and does anything he asks without hesitation. This respect is mutual as Isaak offered Jurg to leave and go home so Jurg wouldn't be hurt by the hitmen that were sent after him. This relationship with his body guard is much more friendly and respectable compared to Jordan's relationship with Cole as he treated Cole like a disappointed little brother and with little respect while Isaak has the utmost trust and respect in Jurg's abilities.
Isaak has been portrayed as a formal and articulate businessman. However underneath this all lies his true nature. He also possesses a similar Dark Passenger like Dexter, but Isaak is completely capable to control his. He can also be very intimidating and philosophical during conversations with potential victims or employees. Isaak has shown a lot of determination regarding the disappearance of his associate Victor Baskov in the process killing those who have/had information about Victor. It is revealed that his relationship with Viktor is very close, suggesting that it was most likely romantic as he is seen very emotional upon entering Viktor's apartment to find a hidden picture of the two of them together, swearing revenge. In Argentina, Isaak would confirm it was romantic as the two were lovers.
His lust for revenge leads him to tracking Dexter Morgan, who he taunts and toys with the ultimate intent of killing. In one instance he is caught in Dexter's trap, where three Colombian mobsters could have murdered him and he simply smiled, realizing the trap before killing all three alone. After the brutal shootout, he smiles and fixes his jacket, taking a relaxed stroll outside of the bar. Even though he's been arrested due to Dexter, Isaak doesn't seem to be angry with Dexter, stating that it's not over and seems to be confident that he'll meet him again. This is proven true as he left prison thanks to Quinn taking evidence on him and remains confident in his hunt for Dexter. Despite his lust for vengeance, Isaak is a very organized and cautious individual, not one to rush ahead without thinking (though he did admit that he walked into a trap set by Dexter due to his desire to kill him, a mistake he stated won't happen again). Of an interesting note, Isaak, while holding a hatred towards Dexter for killing Victor, states they are outsiders and can understand one another and laments that if not for the situation, they could have been great friends. In fact, Dexter himself noted that Isaak actually blames himself for Victor's death, stating if it wasn't for that, he himself would already be dead. In Isaak's final moments of life, he asks Dexter to dump his body to Victor's resting place to be with him one last time and as he dies, Dexter shows regret towards his death and even reveals that he, too, wishes they could have been friends, prompting Isaak to be able to pass away with a smile knowing the two were at peace at long last. Dexter himself even showed genuine sadness over Isaak's death and honored his final wish.
Isaak was born on May 25th, 1964 sometime after the death of Nadezhda Obukhova in Kiev, Ukraine. In his childhood he had a music teacher named Mr. Chillich that Isaak had pushed down a flight of stairs. His reason for doing this comes from what Mr. Chillich told him: “Isaak, you think you’re strong, but you are not strong if you don’t feel.” resulting in an F. His father in response would ship him to a disciplinary school in England, which explains his British accent.
Before his time, he had a great-uncle that served in the Red Army that was loved and cherished by his people in Kiev. A Soviet Party Official became jealous of this fame, attempting to make an example of him by taking away his great-uncle's house. After protesting, he was hung...and Isaak's grandfather (who was just a teenager at the time) had an intense hatred in his eyes thirsting for vengeance. The official had him arrested and sent to Siberia, until the Soviet Union fell and Isaak's grandfather was released to celebrate with all the others in Kiev. It was there that he found the party official and having been patient for many years awaiting vengeance, shoved a six-inch knife into his kidney ending the man's life.
Prior to Season SevenEdit
Isaak became a high ranking official in the Koshka Brotherhood, which is involved in illegal human trafficking and drug trade. At this time he had romantic relationship with one of his subordinates, Viktor Baskov. Viktor would later make his way to Miami where he was sent to keep the Colombians from taking over the Brotherhood's traffic, something that George Novikov was unable to do on his own.
Viktor kills a CopEdit
Shortly following the death of Travis Marshall, a dangerous man known as the Doomsday Killer, Detective Mike Anderson (one of the leading investigators in that case) drives towards his home when he spots a car parked alongside the road. He steps out and sees a man attempting to fix it, asking if he can help. Unfortunately for Mike he discovers the body of Kaja Soroka lying dead in the trunk and before he can react, the man shoots Mike in the chest then finishes him off on the ground with another shot. The shooter is Viktor Baskov, one of Isaak's closest subordinates and part of the Koshka Brotherhood. After wiping down the car, the weapon and making sure to take the jewelry (which contained a GPS chip designed to keep track of their mules) from Kaja's body, Viktor drives off in Mike's car leaving him dead on the concrete, contacting either Isaak himself or someone within the Koshka Brotherhood notifying them of his mistake in killing a cop. He's arranged a flight to leave Miami immediately for his own safety to return to Kiev, Ukraine.
The next day Dexter Morgan arrives on scene and discovers the identify of the killer from a fingerprint lifted from the turn signal of Viktor's car. He keeps this information to himself, seeking a new victim to kill and eventually captures Viktor at the airport he intended to leave Miami from. During Dexter's ritual not much information is learned as to who Viktor is or why he did what he did, but Viktor asks if someone hired him to kill him. Dexter confirms it's just his own doing and before killing Viktor, Viktor asks if there's any way that he can convince Dexter not to kill him. Dexter replies with a no and Viktor says to "get it over with", something he agrees to by wrapping Viktor's head in plastic then taking a nearby fire extinguisher to smash Viktor's skull in.
As Miami Metro Homicide seeks answers as to who shot and killed Mike Anderson, they discover that the victim worked at a night club named the Foxhole, which is run by George Novikov. They stop by asking questions about who could have killed Kaja and Mike, George's initial responses being that "he doesn't know anything about it". After beating around the bush a bit, George finally gets some peace and puts a call in to his boss Isaak Sirko.
Isaak is at his in Kiev, Ukraine when the call comes in to his associate Jurg Yeliashkevych, that tells Isaak that it's "George" and Isaak answers the phone. George tells him that Viktor made his flight and arrived in Kiev at 5:25 Isaak's time. Isaak says "good", then inquires about the dead police officer. George confirms that it's still a problem though he'll take care of it, with Isaak once again saying "good". He hangs up the phone and hands it to Jurg, while Isaak sits there to himself giving a smile feeling Viktor's safely back in Kiev before returning to his work.
Tensions continue to rise between the Miami Metro Police Department and George Novikov, as they start shutting down the Foxhole twice a day seeking answers about Mike's shooting. George continues to grow frustrated by this event, with detectives questioning the workers there. Nadia speaks with Detective Joey Quinn about a Tony Rush, who was dating Kaja Soroka (Viktor's victim and the reason for Mike Anderson's death) and this gives the police a potential lead. They question Rush, who eventually cracks and reveals the name of Viktor Baskov. Sergeant Angel Batista, along with Quinn and the officers from the previous shutdowns arrive asking about Viktor, which surprises George as he has no idea how they got his name.
They decide to head out and George walks into his office, sighing as he puts down his keys and takes a seat. Isaak can be seen sitting in the chair by the window, asking if George had a "rough day". George casually says "Isaak", before correcting himself to be more honorable in saying "Mr. Sirko" and asks what he's doing here. Isaak claims he overheard the police about Viktor and says he's here for the same reason - to find him. George states he has no idea how they found out his name, which Isaak says he's "sure" about but that they'll get to that later.
Jurg Yeliashkevych then walks in, closing the door behind him as he stands sternly at the door staring at George which slightly makes him nervous. He then goes on to say he thought Viktor was in Kiev with Isaak, which results in Isaak asking why he'd be in Miami if Viktor was in Kiev. He states that Viktor never made his flight and that he had checked. Isaak stands up and talks a bit about Viktor saying he's done some stupid things without denying it and says that Killing a policeman is never good for business, then gets closer towards George with a hint of suspicion in his voice as he interrogates his subordinate.
Isaak: I can't help but wonder...if someone in the Brotherhood decided to make an example of him.
George: Without your approval? No. No-no, Viktor was impulsive yes. He did a stupid thing, yes. But he was one of us and we would always protect him.. Isaak puts his hand to George's cheek and leans in with a serious expression.
Isaak: You're in luck.
Isaak: I believe you.
Isaak backs away with George sighing in relief, possibly knowing that his life was in danger and Isaak had suspected him of something to do with Viktor's disappearance. He removes his jacket and tells Jurg to leave the two of them, saying he had a long flight as he seats himself. He then says they have a lot to discuss, learning then of the victim Kaja Soroka that Viktor had killed, her connection to Tony Rush and that he had been previously questioned about her murder resulting in him leaking the information to the police. Isaak personally feels that Rush may have had a hand in Viktor's death, considering he loved Kaja and may have killed him out of revenge.
Isaak, Tony and a ScrewdriverEdit
Isaak and Jurg arrive at Tony Rush's house, walking into the garage as Rush works on his motorcycle. He first steps over Rush, which surprises him and he stands up asking "What the fuck? Who the fuck are you?" as he sees Jurg standing at one end with Isaak at the other. Isaak tells him that he's his employer (then corrects himself by saying "former employer") as he heard that Rush recently gave notice. Rush claims that George is (or was) his boss, before learning that Isaak owns the Foxhole and other associated clubs among various enterprises. Rush asks what he wants and Isaak creates a story about an "exit interview" before slowly questioning him about his reason for leaving involving the death of Kaja. Rush can be seen becoming more and more distraught with emotion as he continues talking, even becoming nervous as he looks at Jurg and back at Isaak.
Isaak claims that he had Tony followed (to which Tony denies that he told the police anything), before acting as if he was only joking with a cracked smile. He says that Rush was just the most likely candidate, that's all. Tony continues to get more and more emotional, his nervousness growing as Isaak comes closer.
Isaak: You loved her, didn't you?
Isaak: Kaja. You were in love with her. It's nothing to be ashamed of. It's the one thing that gives meaning in this life...I would have done the same thing if I was in your position. It's terrible...to lose someone you love.
With Rush's defenses weakened, almost in tears thinking about Kaja, Isaak grabs a nearby screwdriver off the workstation and stabs it directly into Tony's right eye quickly. He steps back as Tony twitches and shudders, before falling to the floor dead. Isaak looks at his body with a calm expression, taking a moment examining his work before stepping over the body and exiting the garage. Jurg moves in and wipes down the handle of the screwdriver before also walking off.
"Who is Dexter Morgan?"EditHe later has a talk with Nadia, one of the strippers about her relationship with Quinn and tells her to get close to him to learn more about Victor's disappearance. He tells George about the bracelet Victor stole and that it has a GPS in it and that Victor is smart that he likely took it so the police couldn't identify it. He asks Jurg to find the man who designed it and that with it, they can find Victor. They find the man who designed it and discover that Victor is eight miles out to sea, resulting in Isaak to become enraged realising he's dead and that he was dumped in the ocean like garbage. He has the designer pinpoint the location from the marina he was dropped off at and, though it will take some time, Isaak says it will be worth the wait. While he waits, he unknowingly talks with the man who killed him in a casual conversation, Dexter Morgan. He tells Dexter to relax since he looks tense and becomes surprised he's not here for women or alchohol and jokes saying he may be in the wrong place. Dexter takes notice of him being from another country and asks what he's doing here and Isaak says he's looking for something, something Dexter can agree with. Isaak notices they're both there just killing time and notices how ironic it is that they're here for a different reason and yet the net result is the same: their both frustrated, something Dexter agrees with and hopes he finds what he's looking for, unknowningly wishing Isaak in finding the man who killed Victor. Isaak then goes to Victor's apartment and finds a picture of him and Victor in Kiev and starts crying over his death and swears to Victor he will avenge him. Later, he comes across Louis Greene at the Slice of Life and kills him after Louis gives him the name of the owner, Dexter Morgan. He returns to the club and runs over both Dexter and Louis's files about their connection to the police department and deduces Victor's death was revenge for killing Anderson. He then defends Victor from George's insults stating he was a good man and refuses to let him speak ill. When George question's why the police are still coming by, Isaak knows this must be off the radar and that Dexter killed Victor without them knowing and decides to give the police someone else to take the fall, looking at Alex Dubrozny and decides to use him as a fall guy. Isaak, George and Jurg visit Alex at night and coerce him to commit suicide to make the case with Mike Anderson go away and take the eyes off the Brotherhood, but Isaak promises to send his family money for his death, which Isaak does. The police arrive the next day and believe Alex is their killer for Anderson, though Angel doesn't believe this and Dexter knows Victor is the one who killed Anderson.
The Hunt for Dexter and ImprisonmentEdit
As Dexter is about to enter his apartment, he notices his curtains are open slightly and realizes someone was in his apartment and believes they might still be as Isaak is in his apartment waiting for him and kill tools to kill Dexter. Dexter leaves a message on his machine to meet someone at a restaurant in an hour and Isaak realizes thats about to happen and leaves disappointed. As he leaves the apartment, Dexter notices him and recognizes him from the club and realizes the Koshka Brotherhood found out he killed Victor and sent a hit man after him. Isaac then goes to a restaurant for a small coffee and gets a call from Dexter asking why he was in his apartment, prompting Isaac to react in amusement. He answers that he wanted to have a "chat" with him about a friend that went missing, prompting Dexter to note he's referring to Victor. Isaac then brings up Louis that was on Dexter's boat to dump Victor in the ocean, confirming Dexter's thoughts that Louis was killed on his boat and Isaak did it, which Isaak said they did have a talk that ended abruptly and Louis gave him Dexter's name and how he referred to Dexter as a "douche bag". When asked if a boss payed Isaak to do this, Isaak is amused and says he's done his homework there are no bosses telling him what to do and that Victor was a friend and that this is personal. When Dexter brings up that Victor killed and innocent woman and a cop and believes killing him settles the score, Isaak says not and that he's not stopping with him and wants all his cop friends involved with this vendetta, including Debra and that he's also done his homework also on Dexter. Dexter yells that only he killed Victor and no one else was involved. Isaak sees Dexter from a distance and says "hello handsome" and agrees with Dexter's statement about seeing each other stating "thats the plan".At the crime scene with Hannah Mckay, Isaak follows Dexter after he's done there and Dexter goes into a Colombian bar saying "Koshka's" to let them know of Isaak and when one of them checks on Dexter in the bathroom, he's long gone. Isaak goes in with a gun and sees three Colombian's and, realizing Dexter set him up, smiles in amusement and successfully kills all three Colombians while only getting a minor graze on the head from a gun and a knife wound on his left forearm and walks out smiling. He arrives back at the Foxhole being patched up by Jurg and after seeing Joey Quinn at the club with Nadia and hearing George that Quinn does anything for them for money, he has Jurg put money in his car. Isaak would later be arrested for killing the Colombian's, yet isn't angry and confident he'll get out.
At prison, he's visited by Dexter who questions Dexter if he killed Victor over Anderson's death and when Dexter says yes, Isaak notes the brief hesitation in his voice noticing he's lying. When Dexter asks if it's now over, Isaak warns him it isn't and that they'll see each other again and wonders what Dexter really is. While in prison, Isaak is visited by a Colombian gang leader warning him about killing three of their men, but Isaak easily incapacitates him with an arm lock and notes even if he kills him, his men will retaliate against his and the Koshka's are stronger and outnumber him and outsmart him in his opinion and takes a phone from his hand and breaks the leaders hand. Isaak then calls George to visit him in prison stating he may not last much longer at this rate. He visits Isaak and Isaak asks about Quinn and George states Quinn returned the money, which is odd to him since he's never done that before, prompting Isaak to tell him not to disappoint him.George then decides to privately talk with Quinn in place of Nadia and warns him about their past together and that if he doesn't listen to him, Nadia will suffer and be deported. When asked what to do, George tells him to take the evidence from lockup at Miami Metro on Isaak away and if he does this Nadia is a free girl and Quinn angrily agrees. Quinn goes into evidence and takes the blood samples away from Isaak that linked him to the crime and walks out angry and frustrated from the order he did.
An Early Release and Resuming the HuntEdit
Due to the evidence having gone missing, Isaak is released from prison and is greeted by Jurg and George, however, he has police officers to tail him from Debra and as George suggests he leaves Miami, Isaak says not yet and that Miami is still overpopulated by one. He visits Dexter at a restaurant and comments on the food. He assures Dexter he isn't here to cause harm, yet, due to his police friends tailing him. When asked what he's doing, Isaak says that while he's waiting around to kill him he might as well get to know Dexter more. He comments that while he was in prison he marvels that he was so determined to get revenge for Victor's death that he was blinded by his desire for vengeance that is caused him to be lured into a trap and assures Dexter won't happen again. Dexter makes their situation like the cartoon "the Coyote and Roadrunner" and how the Coyote never catches the Roadrunner and just "rocketskates right off the cliff each time". Isaak chuckles from this and states he has his motivation for killing Dexter but doesn't understand what drove Dexter to kill his friend. When Dexter says it was to avenge Anderson, Isaak knows he's lying since he knew Anderson for less than three months and feels he's a different kind of animal and asks what kind of animal he is. As Dexter tells him how he killed Victor, Isaak shows anger and warns him he's gonna regret having told him that and leaves with a tip for Dexter letting him have some of his food.
Isaak managed to get rid of his police officers tailing him by having a decoy going out the Foxhole club and stepped into his car, with himself coming out later and driving away alone in another car. He sought out Dexter and after finding him at a donut bar, he tries to shoot Dexter, but misses his target and drives away. In the mean time, George fears that Isaak's obsession for revenge might explode in the face of the Koshka Brotherhood and calls to Kiev. George, with approval of the Brotherhood, hires an assassin to take care of Isaak in his own apartment. However, this fails as Dexter, also attempting to kill Isaak in his home, is forced to kill the assassin by slitting his carotid artery. The Miami Homicide Department, including Debra, Masuka, Batista and Dexter himself, comes to investigate the murder, with Isaak himself being present. When Dexter describes carefully what happens, Isaak jokingly remarks he couldn't described it better if Dexter did it himself, insinuating he knows that Dexter is responsible. Dexter calmly replies with 'Thanks', before leaving the investigating to Masuka.Later, Dexter follows Isaak by driving in Hannah McKay's van to a gay bar. Dexter plans to sneak in, inject Isaak with M99 and take him to the fan like a friend helping a drunk pal to a car to mislead the police escorts following Sirko. When Dexter walks to Isaak, the latter attempted to pick his gun, but Dexter remarks that he cannot kill him here, to which Isaak calmly replies he can but he won't. Isaak orders a bear for Dexter, so they could both relax. Dexter notices they are in a gay bar and deduces that Isaak's enemies wouldn't follow him to it, to which Isaak replies he simply feels comfortable here, implicating he is gay. Dexter tells Isaak to cut his losses and go home to Kiev, to which Sirko replies that thanks to Dexter, there isn't anything waiting in Kiev, since Victor is dead and the Brotherhood turned onto him. Isaak reveals that he and Victor were indeed lovers. Dexter states they both don't have to do what they do, but Isaak replies he has to do it prompting him to ask what Dexter did to Trinity for killing Rita. Dexter says it's nothing he wouldn't of done nor he wouldn't a thousand times over, but Dexter states killing him would not bring Victor back, as neither did the killing of the Trinity Killer bring back Rita. When Dexter asks Isaak what he will do when he finished killing him, Sirko replies he will look for a nice corner of the world to wile his days in comfort and anonymity. Isaak said they are both outsiders, watching the people around them, pretending to be like them but knowing they are not. The best they could hope is find a place where they don;t have to pretend. Isaak states that they could have been great friends under different circumstances, before leaving money to pay the drinks they had and walks away, saying "Till nect time". Isaak is seeing later in a room listening repetitively to the voice message of Victor saying he would arrive soon in Kiev, with sorrow on his face.
Teaming up with Dexter and a Final Resting PlaceEdit
Isaak Sirko is in his hotel room discussing with Jurg about the two assassins George hired, Benjamin Caffrey and Oleg Mickic . Isaak did business with the two men in the past, so he tries to persuade Mickic to drop the hunt. However, Mickic replies that he has his contract and will continue with hunting Isaak. To get help, Isaak goes to Dexter's apartment, where the latter was just about to go to work. Isaak asks for Dexter's assistance in killing the two hitman, in return for his life. Dexter declines and Sirko leaves. When Dexter returns to his apartment after investigating a crime scene, Isaak is present and had made tea. Isaak asks for Dexter's assistance again, this time in return for Hannah McKay's life, who has been captured and held hostage by Jurg. Dexter tries to pin Isaak to a wall with a knife, but Isaak says if Hannah wasn't important, he'd be dead prompting Dexter to back off. He tells Isaak that he's got the wrong guy, but Isaak knows better, stating that he killed Viktor and the hitman after him knowing Dexter has done this kind of thing before. Dexter eventually reluctantly agrees.
Dexter quickly disposes the Mickic, at a shooting range. Dexter visits Isaak hiding in another hotel room and asks to speak with Hannah through Isaak's cell phone. While speaking with Hannah, Dexter snaps a picture of Hannah and the room she is held and sends it to himself. Isaak suspects something is wrong, as Dexter touches the screen, which is not necessarily for a phone call. They have an heated argument about Victor's death, in which Isaak holds Dexter at gun point. Dexter pushes Isaak by saying that he himself is responsible for the death of Victor by sending him to Miami, resulting in Isaak to eventually lower the gun angrily, telling him to leave. While Dexter is investigating another burned victim in the elevator of a parking garage, Caffrey is watching him. Isaak comes up with a plan involving Dexter to lure Caffrey to a docked ship in the harbor, belonging to the Koshka Brotherhood. When the hitman approaches Dexter on the bow of the ship, Isaak shoots and kills him. Dexter and Isaak throw the body in the water, before they both throw away their weapons as a sign of trust. Isaak then just says "see, man of my word" and now promises he'll leave Miami and Dexter alone. Dexter offers to hose away the blood spatters of Caffrey, when Isaak walks away into George Novikov, who sees the gun and mocks George asking him what is he waiting for and shoots Isaak himself in his gut from point blank range. When George is about to finish Isaak, he hears Dexter approaching and leaves. Dexter offers to bring Isaak to a hospital, but the latter knows he is dying as the bullet is still inside. He asks Dexter one favor: to bring him to the place were Victor Baskov was dumped.
Sailing on Dexter's boat, they have a conversation about how Dexter could be fearless, while he seems to be afraid of living. Dexter replies that death usually calms him, as it is predictable, and inevitable, and with a knife in his hand he controls whether he lives or not. But since he met Hannah, he feels like he has no control over his life. Isaak replies that he was the same in the past, detached from the world, hiding a secret, until he met Victor, and that he finally felt alive.
With his last breath, Isaak tells that there is still hope for Dexter, and dies, leaving Dexter genuinely sad over Isaak's death regretting that they really could have been friends. Dexter honors Isaak's final wish and throws his body in the ocean, allowing him to rest in peace and be together with Victor again.
- My music teacher, Mr. Chillich, he said to me, “Isaak, you think you’re strong, but you are not strong if you don’t feel.” He gave me an “F,” so I pushed him down a flight of stairs. I felt bad about it. After that, my father shipped me off to a disciplinary school in England. Now I’m afraid my love of opera is all that’s left of my sensitive side - Isaak, to Nadia.
- I had a great-uncle, my grandfather's brother. He was a hero, fought for the Red Army during the second World War. When he returned to Kiev afterwards some fat little party official...resented the fact that everyone admired him. So he decided to make an example of him...by taking away his house. When my great-uncle protested, he was hung in front of the counsel chambers. My grandfather was just a teenager...when that party official saw that hatred in his eyes, he had him arrested and sent to Siberia. And the years rolled by...and my grandfather got on with his life the best he could. He was a patient man. Finally, when the Soviet Union fell, he returned to Kiev to celebrate in front of City Hall with all the others. And thats when he found that fat little party official...and he got to enjoy the pleasure that belonged to him and him alone. By sticking a six inch knife into that fat little man's kidney. So you ask when...if this is over. No. I'm afraid not... - Isaak to Dexter, who asked if Isaak's quest for revenge over Viktor's death was over (when he was incarcerated).
- Mr. Chillich - Isaak's music teacher in his childhood, pushed down a flight of stairs. Possibly killed.
- Tony Rush - Former employee of the Foxhole and connected to Kaja Soroka (whom was also connected to Viktor Baskov). He was killed with a screwdriver rammed into his right eye.
- Louis Greene - Former intern for Miami Metro Homicide, a video-game designer and antagonist for Dexter Morgan. He was killed to prevent witnesses after learning of Dexter Morgan, Isaak shot him in the forehead with a silenced pistol.
- Alex Dubrozny - Bartender for the Foxhole. He was coerced by Issak to shot himself in the head with the same gun used to kill Detective Mike Anderson after writing a note implying he killed Kaja Soroka, Mike Anderson and Tony Rush.
- Three Colombians - Dexter intends to kill Isaak by allowing the rival Colombians, lead by and including Andres Rodriguez, to murder him after being lured into a bar. Isaak realizes that he was led into a trap and smiles, before quickly shooting and killing one after the other in the bar. He bashes a bottle over the final victims head, before finishing him off by a strong downward thrust of his foot, stomping into his skull.
- Oleg Mickic - An assassin after him. Isaak coerced Dexter Morgan to kill him after kidnapping Hannah McKay.
- Benjamin Caffrey - An assassin sent after him. Isaak shot him to death with a silenced pistol after Dexter lead him into the trap.
- Dexter Morgan - Tried to ambush inside his own apartment but failed when Dexter realized someone was inside. Later, tried again when following Dexter but was lured by him into a trap with three Columbians and sent to prison for a short time. Later, tries to shoot him in a drive-by but fails again. He eventually decides to stop hunting him and allows Dexter to live, so long as Dexter helps rid the two hitmen after him.
- Isaak Sirko is the wealthiest as well as the most powerful main antagonist in the series. The only other antagonist that compares is Jordan Chase, who made millions on his motivational self-help books and conventions. He even had his own major office building and security force, although Jordan Chase was frankly, not an accustomed fighter and thus, not as openly brutal and lethal as Isaak.
- According to the podcast of Michael C. Hall, Isaak was initially meant to be killed by Dexter and used as a bait to lure LaGuerta in the season finale, although the scheduling conflicts prompted them to change the script.
- Isaak is the second Main Antagonist have a loved one be killed by Dexter (Viktor Baskov).
- Isaak is the fourth main antagonist who's not a serial killer, or at least not known to be one.
- Isaak is also the only main antagonist to be killed by another antagonist and overall the second Main Antagonist to be indirectly killed by Dexter.
- Unlike the previous seasons, in which Dexter was trying to catch the antagonists, Isaak is the one who is trying to track down Dexter. The reason for this is to avenge his lover Viktor Baskov, the killer of Mike Anderson and one of Dexter's more recent victims.
- Isaak has a love of opera, stating that Nadezhda Obukhova is one of the singers that he listened to often in his youth.
- Isaak's favorite drinks are small coffee's, as he's seen drinking at least one in every episode.
- Isaak is the third main antagonist to have his body thrown into the water, however, he is the first to not be chopped up and still has all his clothes on.
- Before causing someone's death, either by his own hand or otherwise, he almost always appears calmly speaking. He will become friendly with his victim, smiling and getting them to lower the defenses before either immediately killing them or proposing something darker.
- Viktor Baskov and Isaak were lovers. At the end of the episode "Run", he looked at their photo and weeping as he says he will get revenge. Close to the end of Argentina, Isaak reveals that he and Viktor were in an intimate relationship, telling this to Dexter in a gay bar.
- He is known as Vobk (Vovk), which is Ukrainian for "The Wolf". Interestingly enough his appearance is similar to that of a wolf, with his bright green eyes and darker grey hair. He often wears grey suits and smiles prior to taking his prey...with his expression being fixated, intense and murderous.
- The correct spelling of the word "wolf" in Ukrainian - BOBK (Вовк). The Ukrainian and Russian letters not used "b" - only "B", which reads like a V. Wolf in Russian - "Волк" (Volk). However, the Interpol entry in their database lacks the correct characters in the text and simply spells it "Bobk".
- "Isaak" is a very rare name in Ukraine. On the contrary, Sirko (Сірко) is a frequently used Ukrainian surname. Also, "Sirko" is traditional name for wolf-like dogs and descended from the Ukrainian word for the grey color of dog/wolf fur. "Sirko" is correctly pronounced with the accent on the second syllable.
- Isaak is the second main antagonist in the series to not die in the season finale, the first being Miguel Prado in Season 3. Also, while both of them were once considered "friend" by Dexter, they are almost polar opposites. Miguel begins as a honorable lawman who trusts Dexter almost to a fault but ended as hateful murderer and personal enemy of Dexter while Issak is entered as Dexter's most powerful personal enemy and a mobster at that, they reached an understanding of sort near the end.
- Isaak's favorite weapon is a Makarov IJ70-17as with a chrome finishing. Caliber 9x17 (.380ACP).
- Following Season 2, Dexter begins dumping any victims he's brought out to sea into the Gulf Stream's currents, with their body parts floating up through the country making it difficult to trace to him. For some reason Dexter chose to dump Viktor in a spot where his body remained in one location, the same location he dumps Isaak's body.
- Under normal circumstances, if Viktor was dumped into the stream, then it would be highly unlikely for Dexter to "reunite" the two if Viktor's halfway up to Canada. Though in the story it appears Viktor was omitted from the stream.