Karis is a character in Superstition, one of the playable characters in the game. Karis is the younger brother of Sytha and the best friend and roommate of Lucky, who is often there to help Lucky through his anxieties on a regular basis. In Superstition, however, he and Sytha are separated from Lucky during an invasion, and the two go on their own adventure to reunite with him.
Karis, contrary to Lucky's pessimistic nature, is happy-go-lucky and supportive, though it is revealed that a lot of this personality is in attempt to make sure Lucky has some happiness around him. Always keeping an optimistic personality with him, he's generally just a joyful guy. Nothing wrong with that.