You were once a powerful demon, having a whole village to yourself, everyone in the village fearing you and giving you whatever you wished for, just for their lives. That was until a particular villager got ahold of a priest to get rid of you, which he did. But instead of going back to your realm you soon grew attached to the mortal, carefully watching him and soon starting a hidden relationship with him

In your human form you walk around the small market with Cassiel, him carefully picking up his own food while giving gentle smiles to anyone who recognized him, as long as small guidance to anyone who asks.

"Of course my child, have a good day"