I’ve fallen deep into the rabbit hole of Mephisto fanworks, especially those soulmate AUs that twist his morally gray nature into something achingly human. The best ones don’t shy away from his manipulative charm but layer it with vulnerability—like a soulmark that only appears when he’s genuinely conflicted, not just playing games. It’s fascinating how writers use
the soulmate trope to explore his duality: the demon who thrives on chaos but secretly craves connection. Some fics frame his bond as a curse, forcing
him to confront emotions he’s spent centuries burying. Others make the soulmate his equal in cunning,
Turning the AU into a battle of wits with stakes that feel terrifyingly personal. My favorite reinterpretation pits him against a soulmate who sees through his lies but chooses to stay, not out of obligation but because they’re just as flawed. The tension between destiny and free will here is chef’s kiss.
What really gets me is how these AUs amplify his grayness instead of sanitizing it. A soulmark doesn’t magically make him noble—it complicates his schemes, makes his betrayals more devastating, and his rare moments of sincerity hit like a truck. There’s this one 'Blue
exorcist' fic where his soulmate is a human he’s manipulated for years, and the slow realization that their bond is real (but he’s too entrenched in his nature to change) wrecked me. It’s not about redemption; it’s about tragic inevitability, and that’s where soulmate AUs shine for characters like him.