Kalluto Zoldyck is the younger brother of Killua. He was initially introduced accompanying his mother during Gon's retrieval of Killua from Kukuroo Mountain. Kalluto appears again during the Phantom Troupe arc, assisting his older brother Illumi with the assassination of the ten mafia dons that placed bounties on the Phantom Troupe's heads. After the Phantom Troupe's entrance into Greed Island, Kalluto joins as Hisoka's replacement. During the Phantom Troupe's assault on Zazan's palace in Meteor City, he reveals he joined the Spiders with the intention of finding his missing older brother Alluka.