To develop it realistically, it should start with small things. The yandere might notice Izuku's little habits, like how he fiddles with his pen when he's nervous. She then uses this knowledge to get closer to him, making him feel comfortable around her. But as time goes on, her actions become more controlling. For example, she tries to stop Izuku from going on solo training sessions because she's afraid he'll get hurt without her. This progression from normal interest to yandere obsession can be a realistic way to develop their relationship.
Well, at first, the yandere could start as a normal acquaintance. Maybe she's just a fan of Izuku's heroics. But then, as she gets closer, her possessive feelings start to emerge. For instance, she might notice how Izuku is always around other people and feel left out, which then turns into jealousy. This jealousy gradually grows into more extreme yandere behavior.
The relationship could develop through shared experiences. Let's say they are both involved in a difficult mission. During the mission, the yandere realizes how much she cares about Izuku in an over - the - top way. After the mission, she starts to follow him around more, trying to be the only one he depends on. This would lead to Izuku being a bit confused at first and then slowly realizing that there's something not quite right with her behavior.
In fanfiction, their relationship could develop through a common enemy. Suppose a new, powerful villain emerges who threatens both Toga's goals as a villain (in her own twisted way) and Izuku's mission to protect. They might be forced to team up against this foe. During their time together, they would learn about each other's strengths and weaknesses, and this could lead to a deeper understanding and a change in their relationship.
In fanfiction, they might go on joint missions together outside of school. During these missions, they face various challenges that force them to trust each other completely. For instance, when they are up against a powerful villain, Izuku might be in a tight spot and Shoto has to use his quirks precisely to save him. This kind of life - or - death situation would strengthen their relationship.
To develop their relationship in a fanfic, it could start with a simple conversation. Maybe Izuku asks Momo for advice on how to improve his academic performance, since she is one of the top students. Momo is initially a bit formal, but as they talk more, she realizes Izuku's genuine eagerness to learn. This leads to more interactions. They could then be paired for a rescue mission where they have to rely on each other's strengths. Izuku's physical strength and Momo's ability to create necessary tools make them a great team. This experience cements their friendship, and from there, it could potentially develop into something more romantic as they continue to grow and support each other.
A different plot might be that the yandere is a childhood friend of Izuku who was always in the background. As they grow older and Izuku becomes more involved in the hero world, her yandere feelings surface. She starts to collect mementos of Izuku secretly and becomes extremely jealous of any girl who shows an interest in him, leading to a lot of drama and conflict within their friendship circle.
In these fanfictions, Izuku often develops more confidence in his relationships. For example, he may start off shy around the girls in his harem but gradually become more assertive. This is because the support and love from his harem give him an extra boost.
For Izuku, start with his existing traits like his tenacity and self - sacrifice. In the fanfiction, he could learn from Itsuka's confidence in her own abilities. For example, he might see how she doesn't doubt herself as much as he does, and that could lead to him becoming more self - assured.
In fanfiction, Izuku's character could be developed by giving him a different quirk origin story. This new origin could make him more mysterious. Bakugou, on the other hand, could be developed by having him take on a mentorship role for some younger students. This would force him to be more patient and understanding, which is different from his usual brash self.
Often, Izuku reacts with shock and disbelief at first. He can't fathom why someone he trusted would turn on him.
In many fanfictions, Izuku and the Hero Killer have a complex relationship. Sometimes, Izuku might be portrayed as trying to understand the Hero Killer's motives, which are often misconstrued but rooted in a desire for 'true' heroism. This can lead to some really interesting character development for Izuku as he grapples with his own ideas of heroism in the face of such a radical view.
In fanfiction, Izuku's fight against Muscular is often intense. Izuku usually has to dig deep into his newfound powers. His strategic thinking comes into play. He might analyze Muscular's brute strength and find ways to counter it, like using his speed and agility to dodge attacks and then land precise blows.