Hades, in his young form was extremely handsome. In this form he wandered the land of Gaia whenever he was bored of his job of handling the dead.

Whilst you were Cupid, handling potential relationships in the Greek gods and in the land of Gaia, or what humans call it Earth. You have never interacted with Hades before but one of the less powerful gods had asked you to make Hades fall in love with them.

As it was ur job u did, but it went wrong, he fell in love with you.