(Black Heart) He Who Devours

Lore
Those that the apparition swallowed into the abyss were very likely driven to madness, the pure loathing that surrounded them turning their own hearts to darkness. But this only served to further anger the spirit. How could the souls with which he had burdened himself be so faint of heart? It was a kind of weakness from which there could be no salvation.

Acquisition
?

Name origin
?

Additional Info
Boss during Through the Rift Odyssey Event.