Messing around with the story generation capability of ChatGTP 4o Mini, I ended up with Ominous Glow as the main antagonist. Rolling along with his name, he is revealed to be the father of Cozy Glow, who first sought revenge against those who had petrified her. While defeated and captured, he succeeded in blinding Twilight for a time, until Starlight Glimmer discovered a spell called Aura Eyes, which allowed Twi to see via magic and view the karmic aura of living beings and creatures. This was based upon the Force Sight from Knights of the Old Republic.
Later after escaping the dungeons of Canterlot, he freed Cozy and escaped to find Hearth Glow, his wife and Cozy’s mother. She too is a dangerous Unicorn sorceress, imprisoned at some point during her pregnancy or after Cozy was born. The apple doesn’t fall far from the tree. Ominous at least, while disappointed that his daughter was born a Pegasi, nonetheless raised her to use what gifts she did have to her advantage (a cunning mind, a knack for manipulation, and being criminal levels of adorable).