one anime character known for his sadistic smile is Hisoka Morow from the anime series "Hunter x Hunter." Hisoka is a skilled and dangerous character who takes pleasure in manipulating and toying with others, often using a sadistic grin to display his enjoyment in combat and psychological warfare.
Keep in mind that there might be other anime characters introduced who could also possess a sadistic smile or exhibit similar traits. It's always a good idea to check more recent sources for the latest information on anime characters and series.