God Oddities - Janus
Janus covers not only literal transitions and doorways (‘janitor’ derives from the Latin for doorkeeper/porter, from 'ianua’ meaning door), but metaphorical. Prayers to the gods invoke him first as he gatekeeps the gods too. Some myths even place him as opening the way for the… er… “Zeus juice” when babies are conceived.
Janus once accompanied a nymph, Cardea, known for leading admirers on and then running away, to a cave. His behind-face saw her escaping, but he caught her, “seduced” her and made her the goddess of hinges.