The Assassin is a minor villain from the Disney TV series Gargoyles: The Goliath Chronicles.
He was a mercenary, aligned with the Quarrymen, who was hired by Demona to track down and assassinate Goliath, and at the same time, make Demona look like a hero so that she could take over the clan in Goliath's place. The Assassin, in turn, got Quarrymen to work with him to try to trap the Manhattan Clan so that he could carry out his mission.
His first attempt involved having his Quarrymen corner the clan in an alley, and during it, he shot Demona, so that she was supposedly wounded defending the clan. Next, he attacked a hideaway of Demona's where Goliath and Angela were present, but was driven off and had a tracking device "planted" in his boot by Demona. Goliath only managed to get outside, however, before motorcycle-riding Quarrymen captured him, and he was taken to the Assassin's base.
After this, however, he changed his mind, and, after luring the clan into being captured in a trap, he spilled the beans on Demona's entire scheme to Angela and Goliath. Angela was very hurt by this new betrayal, when it seemed her mother had finally reformed. Goliath, however, broke free, and defeated the Assassin. Demona escaped, the clan flew off, and the Assassin has not been seen since.