Izuku's character development in this fanfiction could be quite complex. With a dark matter quirk, he may initially be ostracized or feared by some due to the unknown and potentially dangerous nature of his power. This could lead to him feeling isolated, but it also might fuel his determination to prove that he can be a great hero. As he trains and explores his quirk, he would learn about its limits and potential. His moral compass could also be tested, for instance, if the dark matter has some unforeseen negative effects. Through these experiences, he would gradually transform from a somewhat naive boy into a more mature and self - assured hero, all while grappling with the implications of his unique quirk.
One interesting concept could be how Izuku's dark matter quirk might give him unique abilities like the power to manipulate gravitational forces. It could also lead to a new form of combat style that's different from the traditional quirks in the My Hero Academia universe.
One implication could be a change in his relationships. His friends might be initially afraid or distrustful. For example, Bakugo could see this as a sign of Izuku being a real threat now, instead of just a rival. Also, the teachers at UA might have to deal with a whole new set of problems regarding Izuku's training and control of his dark quirk.
One idea for Izuku Midoriya's quirk in a Dark Souls - inspired fanfiction could be 'Soul Link'. This quirk would enable him to form a link with other people's souls. He could use this link to either heal them by sharing his own energy (similar to Estus Flasks in Dark Souls), or he could disrupt their soul's energy, causing them to be weakened or even stunned. It could also work as a way for him to sense the presence and intentions of others, as he would be attuned to their souls. This quirk would give him a unique advantage in battles and also in forming relationships with other characters in the fanfiction.
Some characters might be immediately terrified. They could avoid Izuku or even try to drive him away. For example, classmates who don't understand his quirk might spread rumors about him.
The Gamer Quirk also changes Izuku's relationship with others. He can now offer unique insights based on his quirk. For instance, he might be able to analyze a villain's attack pattern like it was a boss fight in a game. His friends and allies can then use this information to their advantage. This makes him a valuable member of any team. At the same time, it also means that he might be seen as a bit of an oddball because his thinking is so different from the norm. But overall, it helps him form deeper connections with those who understand and appreciate his quirk.
His relationship with his mother could become more complex. She might be worried about his new nature and try to protect him more. With his friends, like Bakugo, they might initially be scared or distrustful when they find out about his quirk.
In 'The Healer of UA', Izuku's healing quirk is more complex. It requires him to concentrate and visualize the injury being healed. He can also transfer some of his own stamina to the injured to speed up the process. This makes his quirk not only about physical healing but also about his own sacrifice and determination.
His personality could be split. On one hand, he would still have his core values of heroism and kindness. But on the other hand, the dark quirk could bring out a more ruthless side. He might find himself having internal debates between using his power in a traditional heroic way or succumbing to the darker impulses that the quirk brings. This internal struggle would be a major part of his new personality in the fanfiction.
Well, there's 'Izuku's Sword Path'. This fanfic focuses on Izuku's journey with his sword quirk. He has to train hard to master it, and along the way, he meets some interesting characters who help him. The author does a great job of showing how Izuku uses his quirk in creative ways during battles. There are also some emotional moments as he struggles with the responsibilities that come with such a powerful quirk.