Mr. Chillich is a character on DEXTER. Long ago in Isaak Sirko's early life he was a music teacher than gave an "F" to Isaak in class. His quote before Isaak pushed him down a flight of stairs was “Isaak, you think you’re strong, but you are not strong if you don’t feel.”. It is presumed that Mr. Chillich died and Isaak's father sent his son to a disciplinary school in England following this incident.
Due to this, Mr. Chillich could possibly be Isaak's first official kill resulting from what is likely anger. He claims that he felt bad about it, however after being sent to the disciplinary school he states that the only thing remaining of his sensitive side is his love of Opera.