Sadistic, cold and callous, Niles derives pleasure from watching the suffering of others, a fact made plainly evident throughout his supports, where he visibly becomes excited when bearing witness to the pain and discomfort of his conversational partners. These traits of Niles in turn lends to his being an easily agitated individual; through his supports with Arthur, he is observed to, in response to being asked why a wanted criminal like him is permitted to serve a member of royalty, threaten to kill Arthur.