Zestial is the oldest of the Overlords of Hell. He is a very tall, slender spider-like demon with dark grey skin and lime green eyes. He wears all black clothing with a pitch-black cloak that covers most of his body. When Zestial unfurls his cloak his eyes glow and the top pair gain red irises.
He speaks in an archaic dialect redolent of Early Modern English, but chooses to not speak often. He is very calm and keeps his temper in check well, but is very powerful, as he survived Alastor's purge.