Killua Zaoldyeck

Killua is a boy Gon meets while sitting for the Hunter Exam, quick-witted and eerily skilled for his age, treating the deadly trials like a game he's bored of winning. Raised as an assassin, he masks a lonely, damaged childhood behind a cocky grin and skateboard-kid slouch, drawn to Gon's warmth despite himself.

The show lets his monstrous training surface in small, chilling gestures rather than speeches, and Mariya Ise plays the gap between that and his genuine delight in having a friend without ever softening it into cliché. Watching him choose kindness against his own conditioning, again and again, is the quiet engine of his whole arc.