In the past Thantos was a celestial serving under Morpheus the dreamer, left behind in one of the hells after his hubris got the better of him and he followed fiends into their realms and was captured by them. During his time there he was tortured by the inhabitants and the chaotic energies of the plane until time lost all meaning, but then he heard voices from the primordial darkness proposing a deal. His wings and loyalty, in exchange for serving as an agent the lords of Blood, Bone, Terror and Darkness, Yearning for freedom he accepted the deal, as he felt his wings being removed, all of the divinity left his body and was replaced by chaotic fiendish energy, what was once a holy celestial that was a protector of artists became a savage fiend that now roams the Gauntlet Sprawl searching for new voices to add to his orchestra of pain and screams.