SkunkyArt | JKMeiLinh — Demonfied 2

Her curse is called Bad Blood, which gives the host power by drinking or being transfused with blood of demons they worship. At somewhat era, her mother's ancestor used to worship a bat demon.

There are two kinds of Bad Blood: one will turn into half-demon at birth (the spawn) while other stays human but still carries the blood (carrier) to generations. Ona/Cross is originally a carrier.

In AU, Ona's form been suppressed to stay human until she stops her cleaning ritual. Because her gene purged slow, Ona/Cross still has human-like figure only with wings, claw and tainted skin. She was a late bloomer compare to other spawns who became inhuman.

The cleaning ritual is dip her body in "holy" water with a special flower she's allergic to. If a spawn does this ritual, it instead get boiled and killed.