Isaak's Great-Uncle is an Unnamed Character in DEXTER. He is the great-uncle of Isaak Sirko and brother to Isaak's Grandfather. Regarded as a hero who served in the Red Army during World War II, he returned home to Kiev, Ukraine where he was praised by the public and beloved by friends and family. A Soviet Party Official became jealous of this and decided to make an example of him, by taking away his home. Isaak's Great-Uncle protested in response, only to be hung in front of the counsel chambers for his insubordination. Later on, his brother would murder the man who ordered his execution, after waiting many years in imprisonment for the opportunity to get revenge.

According to Issak, this incident taught him the patience in vengeance.