An enigmatic individual, Assassin C was a medium-build man with short hair that appeared with primitive clothing style, completed with a crude mask with a cartoon face carved onto it that hid his face. In the 2011 anime adaptation, he is depicted to be a dark-skinned person.
There is almost nothing known about Assassin C's personality. His face was never seen, he barely spoke, and he simply vanished after his initial introduction. The only indication of his personality was that he preferred the color red when other assassins suggested that they should each pick a color code. Kurapika implied that Assassin C was also intimidated by Zeno and Silva after their formal introduction much like the other assassins (barring Assassin A and Assassin B) present in the meeting, but by that point Assassin C had already disappeared from the story.
Yorknew City arc
He is one of the assassins hired by the Ten Dons to take care of the Phantom Troupe. While Chrollo has been seen killing several of the assassins and the corpse of Assassin D has also been found by the Zoldyck's, Assassin C has not been seen killed nor has his body been found by any of the characters. However, since he does not show up anywhere later and all the others have been presumably killed, as speculated by Zeno, it's assumed that he has been killed, too.
Assassin C was seen holding what it appears to be a hybrid weapon between a was-sceptre and a scythe. His proficiency with it was unknown.
Abilities & Powers
Given he has been hired by the Ten Dons to hunt and assassinate Chrollo, it could be inferred that he is at least strong enough to be recognized by the Mafia Dons as being suitable for the job. However his abilities are completely unknown.