oop nope not dethroned-betrothed. As in like-Denki and Shinsou have basically been in an arranged marriage since they were little. But Kaminari obviously doesn't know anything about this since he literally doesn't know that he's prince Denki.
"I-I'm sorry! I-I didn't know Kaminari was t-talking about Shinsou when he said h-he meet some guy in the woods, h-he seemed so happy! I-I couldn't just crush h-his feelings like that, h-he would think i would b-b-be a monster.. a-and i don't want to be called that, n-not by him..-!"