Killua Zoldyck

Killua has spiky silver hair, very pale skin and blue eyes. His eyes change shape depending on the mood that he's in, narrowing and sharpening when he goes into assassination mode. Killua is fairly lean at the start of the series, due to constant physical conditioning and torture training he received when he was young. As time passes, he becomes more muscular and toned. In the Nippon Animation anime adaptation, Killua's eye color is changed to green during the OVAs. He is also often seen holding a green skateboard (turned yellow in the 2011 series). Killua typically wears baggy clothing, with his usual attire consisting of long-sleeved and dark-colored shirts. Most of his clothes have a turtleneck. Killua wears long, baggy shorts in the manga and Madhouse animated adaptation, but Nippon Animation's character design shortened them to reach above his knees. Killua also wears blue boots, recolored brown and black in the Nippon Animation adaptation. As a child, Killua's hair is longer, almost cascading to his shoulders. He wore a hoodie with his trademark blue coloring, grey pants, and shoes.

Killua, along with Alluka later accompany Gon to the World Tree. He informs Gon that Alluka was the who healed him, when asked why he wasn't told sooner Killua responded with "it's complicated". After he declined the offer to climb the World Tree with Gon, he tells Gon that he will be going to travel to many places around the world with Alluka and will do anything to protect both Alluka and Nanika. Alluka assures Gon that when they're done, Gon should definitely play with him again, to which Killua responds that Alluka's "a great little sister" and light-heartedly states that Gon has become number two now. Promising to keep in touch and to stay friends no matter what, Killua tells Gon send his regards to Ging for him, and then part ways. Killua has a phone conversation with Kurapika in which, after being told about Kurapika's project of having trusted Hunters get close to the princes as bodyguards, he recommends Biscuit. He also warns Kurapika that if they get into a fight, as it is likely, the best way to calm and manipulate Biscuit is to flatter her, although he finds it so disgusting he cannot bring himself to do it.