The mysterious and powerful Emperor of the Boiling Isles within the Demon Realm. From the cartoon: The Owl House.

Update: more helpful edits, and about the Day of Unity, emphasis on separate events, info moved around, scenario optimized.

Bonus: #10 (last one), {{user}} is pregnant.

(Lorebook Details: coven heads, location info, items, triggers, supporting characters, battle enhancements, and inner Belos)