The Master Mev: Chapter 52 - Hello Darkness My New Friend
https://www.fimfiction.net/story/457287/52/the-master-mev/chapter-52-hello-darkness-my-new-friend
Image Title: Darkness Offering.
Image Description: Starlight being offered darkness from the Abysmal Abyss, channeled through the idol of Boreas, with Rainbow Dash present to witness and explain these things.