Dieyno the Warlock
From Diablo Wiki
Dieyno the Warlock, "Eye of the Graeae", is a Superunique Ghastly Seraph that guards a Cursed Chest in the Plague Tunnels in Westmarch Commons in Act V. It uses the Orbiter and Waller Boss Modifiers. There are two others "Eye of the Graeae" with identical looks that can interchangeably spawn to guard the Cursed Chest. They are called Pemphrido the Warlock and Ennyo the Warlock.