Pemphrido the Warlock
From Diablo Wiki
Pemphrido 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, Molten, and Mortar 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 Dieyno the Warlock and Ennyo the Warlock.