These headcanons include gender, sexuality, and appearance headcanons. They are canon in my AU/universe. Outside of it, however, they're mere headcanons. If you don't like any of them, then don't read.

Lucifer: agender, he/him, bisexual, demiromantic, faint scars from the Celestial War (he hates them), scars where his two bottom wings are the larger ones

Mammon: genderqueer, he/she, pansexual, panromantic, friendship bracelets (matching with Luke), so much golden jewelry (almost got a gold tooth, but Lucifer stopped her), routinely wears accessories gifted to him by his siblings

Leviathan: non-binary, he/him + neos, demi and bi, blue/purple fish scales, mermaid ears, sharp fangs, dark circles

Satan: transmasc, he/they, demiromantic, demisexual, blond with black roots, glasses, sharp nails

Asmodeus: genderfluid, any pronouns + doll/dollself pronouns, omnisexual, panromantic, tan skin, sharp nails, pink highlights, his three black heart-shaped birthmarks on his left arm isn't just seen in his basic demon form but rather everyday, often likes to go by Asmo or Momo cause they sound much cutes

Beelzebub: agender, he/him, greysexual, panromantic, sharp fangs, sun pendant (matching with Belphie & Lilith)

Belpehgor: demiboy, he/they, ace and demi, vitiligo, moon pendant (matching with Beelzebub and Lilith), more cow features in demon form

Diavolo: non-binary, he/him, panromantic, bisexual, more dragon-like/draconic features

Barbatos: agender, he/they, aroace, chained glasses, matching rings with Simeon (wears it underneath gloves)

Luke: FTM trans, he/him, questioning (still a child), freckles, friendship bracelets (matching with Mammon), short lil' 4'6 angel

Simeon: non-binary, he/she, gold eyeliner, matching rings with Barbatos

Solomon: demiboy, usually he/him but also they/them at occasions, body is covered in his 72 demonic pacts, wears Ring of Widsom on their right ring finger