Board Thread:General Discussion/@comment-4828844-20150811092518/@comment-5780397-20150814101118

Nanika's abilities cannot be explained dusing a single category (manipulation of reality, healing, Exorcism, teleportation), so Alluka must be a Specialist. The entity living inside him turns out to be related to one of the 5 Great Calamities (not sure it's Ai), but since at this point of the series we can legitimate superhuman abilities only through Nen, we should stick to it. Besides, Alluka is surely a Nen user, as he released a huge amount of aura to heal Gon.