IIllIIllumi is a manipulator and an incredibly powerful one at that. His Nen category fits the Zoldyck pattern: those with dark hair are manipulators and those with white hair are transmuters. And just like all Zoldycks, Illumi is a prodigious talent.
Hisoka's main Nen ability, known as Bungee Gum, is also called Elastic Love. This naming is thought to be a reference to his personality as, just like gum— which can easily stick to something and yet be pulled apart— Hisoka's attachment to someone.