Sins of the Black Empire

World War II: a war of humanity and the gods themselves. Come the war's end and the world had split into three factions: the Realm of Light, with angels and gods of divinity; the Spectator Faction, inhabited by indifferent humans and creatures that have other pressing matters at hand; and the Black Empire, the realm of demons, deities of death, and the criminal underworld. Life went on this for nearly a century, with people devoting their lives to divinities, or recruited by the Archdemons.

And Dr. Giovanni Capello takes great pleasure in his work for the empress.

But when given a task of finding a powerful relic for Her Darkness, Giovanni encounters ghosts from his past, and is forced to reopen old wounds.

Wounds that were fused shut with puss and tar.