In the manga, the relationship between Iruma and Ameri is complex and evolving. But as of now, it's hard to say they end up together. The story is still unfolding and anything could happen.
In many 'Batman Beyond' fanfictions where Dana finds out, it could be about her finding out Bruce Wayne is Batman. Maybe she stumbles upon some evidence in the Batcave or notices some similarities in Terry's behavior to Bruce. For example, she might notice Terry's fighting style is similar to what she's heard about Batman's. It could also be that she discovers some secret technology related to Batman that leads her to the truth.
The theme of adaptation is prominent. Iruma has to adapt to the completely different and often crazy rules and customs of the demon world. Also, there is a theme of defying expectations. Despite being a human in a world of demons, he manages to exceed the low expectations others initially have of him and rise to great heights.
Clara is an important character. She is a very energetic and somewhat unpredictable demon. She befriends Iruma early on and is always getting him into all sorts of strange and fun adventures. Then there is Sullivan, the demon who bought Iruma. He acts as Iruma's grandfather in the demon world and is very powerful and protective of Iruma.
Sure does! As the story progresses, Iruma fulfills the role of the demon king. It's a significant development that fans have been excited about. The plot builds up to this point with various challenges and growth for Iruma.
Ginny's reaction could also involve a sense of helplessness at first. But then she'd quickly gather herself and use her resources. For instance, she might call on her friends and family for help. She'd be by Harry's side constantly, using her presence to comfort him and also using her knowledge of magic to try and ease his pain.
For Merlin, there are both good and bad consequences. On the bad side, some of the more traditional and anti - magic people in Camelot might try to oppose him. However, since Arthur now knows, he has a powerful ally. Arthur can protect Merlin from those who would do him harm. Also, Merlin can now be more open about using his magic for the good of Camelot, which is a positive change.