Looking to add more details for Mother Night

Hello all!

One of my players is a cleric of Mother Night. Her background is that she is a dhampir from Barovia who was taken outside the Mists and abandoned in the woods. Her adoptive father, Stefan, who is a homebrew NPC, was a werewolf from Barovia who escaped. He brought our cleric, now named Celeste, to his home, where he lived with other devotees to Mother Night.

I'd love to be able to bring a side quest in relating to Mother Night. My players have been trying to find information about Mother Night, but the book RAW says nothing much about her other than the werewolf Shrine and Baba Lysaga being the main things. I would love to have a little side adventure where they can learn more about Mother Night, maybe even something like steal X thing from Baba Lysaga and bring it to the Shrine.

I love the idea of the duality of Mother Night being a sei-mix of Selune and Shar - both the light of the moon and the darkness of night. Maybe something can be incorporated here with this?

I'm not 100% sure but I'd really like to hear your ideas on this. Thanks!