One common theme is the struggle for acceptance. Since she's a female in a world where the main character was originally male, she often has to prove herself more. Another theme is friendship. Female Izuku's relationships with her friends, like Bakugo or Todoroki, are often explored in new ways.
One popular MHA female Izuku fanfiction is 'She - Izuku Midoriya'. It offers a unique take on Izuku being female and explores how her character would interact differently in the MHA universe. Another great one is 'Female Izuku: A New Heroine'. It delves into the challenges she might face as a female in a male - dominated hero world and how she overcomes them.
One possible consequence could be the extreme shock and grief among his friends and allies. They would likely be devastated and it could lead to a downward spiral in their morale. For example, his classmates like Ochaco might blame themselves or become extremely angry at the situation.
Communication is key. In the fanfiction, they could start having study sessions together. As they talk about their hero theories and strategies, they also start sharing personal stories. Shouto might open up about his relationship with his father, and Izuku could talk about her journey to become a hero despite being a girl in a somewhat sexist society. This will make them understand each other better and bring them closer.
Bakugo might initially be in denial. He's always had a complex relationship with Izuku, and seeing him in such a state could shatter his world view. He might become more withdrawn or, on the contrary, be spurred into a violent rage against whoever was responsible.
One plot idea could be that female Izuku and Shouto are paired up for a special hero training mission. They start off not getting along well because of their different approaches to heroics. Shouto is more by - the - book while Izuku is more instinctive. But as they face various challenges during the mission, they begin to understand and respect each other's methods, and a romantic bond starts to form.
One fanfic I remember has the OC reincarnated as Izuku with the power to manipulate time on a small scale. It's really cool because he uses this power to analyze battles and opponents' moves more effectively. He can slow down time for a few seconds during combat to gain an advantage, which is a very unique take on Izuku's character development.
To some extent, it is popular. There are many online platforms where MHA adult fanfiction can be found. The popularity might stem from the fact that the MHA world has a rich cast of characters and a complex universe. Fans who enjoy adult - oriented storytelling might use these characters to create their own narratives that are more in line with their interests in terms of relationships, power dynamics, and personal growth, all with an adult twist.
Several characters have met their demise in the MHA manga, but it's a bit complex to list them all precisely. Some of the notable ones include [mention specific characters if known].