One scenario could be that Izuku is on the roof to get some fresh air and clear his head. Aizawa, being the observant teacher he is, follows him there. He could then share some of his own experiences with Izuku, like how he overcame difficulties in his youth, which would inspire Izuku and strengthen their relationship in the fanfiction world.
Perhaps Izuku was skipping class and went to the roof. Aizawa noticed his absence and suspected he might be there.
In some fanfictions, Aizawa might be under the influence of a villain's quirk that makes him act against his will. So, he kidnaps Izuku, but later on, he realizes what he's done and tries to make amends. This could lead to a story full of drama and redemption.
Well, Aizawa might be a bit surprised at first. He's a no - nonsense kind of teacher. He could either be intrigued by the creativity of the fanfiction or be a bit put off by it, thinking it's a distraction from the real training and hero business. He might also tell Izuku not to get too caught up in fictional ideas and focus more on improving his real - life skills as a hero - in - training.
One reason could be that Izuku has been pushed to his limit. Maybe Aizawa has been overly critical or strict in a way that Izuku can't take anymore. For example, if Aizawa constantly doubts Izuku's abilities despite his efforts, it could lead to Izuku snapping.
Well, it could be about Izuku confronting Aizawa over some misrepresentation in the fanfiction. Maybe Izuku doesn't like how Aizawa is being portrayed as too strict or unfair in the fic.
It could be Aizawa himself if he's being controlled by something or has some sort of ulterior motive that is not in Izuku's best interest. But if not Aizawa, then there could be a hidden villain who is manipulating Aizawa to kidnap Izuku.
In this fanfiction, Izuku might learn valuable lessons from Nana. Maybe she could train him in some unique ways, sharing her own experiences as a hero. Their meeting could also lead to Izuku getting some new inspiration for his hero costume or his fighting style.
Well, in this fanfiction, Izuku and Nejire might start as strangers and gradually become friends. They could discover each other's unique quirks and powers. Maybe they'll team up to face some common enemies or challenges in their hero training. It could also be a story where Nejire helps Izuku gain more confidence in his abilities.
In this fanfiction, Izuku might show the Avengers his unique quirk. Maybe he'll be in awe of their superpowers at first. Then, they could team up to fight a common enemy, with Izuku's strategic thinking from his hero training and the Avengers' combat experience combining for an epic battle.
One good one might be 'Aizawa's Guidance for Izuku' which focuses on their unique mentor - mentee relationship evolving in an interesting way. It has great character development.