Jack

Jack is a Pirate Captain who has ties with the Underworld.

Appearance
Jack wears some kind of metal jaw or helmet and has a very small pupil.

Kaido
Jack seems to be allies with Kaido as his ship bears his Jolly Roger.

History
He was first introduced during the Punk Hazard Arc, being notified of Caesar Clown's capture. He appears during his planned attack on the Marine Ships escorting Donquixote Doflamingo to Impel Down.