Salam, I am 13 year old girl who watches anime, and there are so many men characters that I love and have sexual thoughts about them. But instead of imagining them in real life I imagine myself with them in the fictional world kissing or something like that. Is this haram? If it is, then why did Allah give me a couple dreams of doing that stuff with my anime crushes? And what do I say/do to ask for forgiveness??
Yes, it is, especially in Ramadan. Allah didn't give you these dreams. You're simply influenced by what you've watched which is why you kept having erotic dreams of these characters.
To repent, simply ask Allah for forgiveness, try your best to stop having these thoughts, and stop watching the animes that influence you to have these thoughts.