Another place to find this kind of fanfiction could be FanFiction.net. It has a large collection of My Hero Academia fanfictions, and you might be able to find some great 'izuku has black blood' stories among them. Browse through the My Hero Academia section and keep an eye out for the specific concept.
One interesting 'izuku has black blood fanfiction' could be where his black blood gives him unique powers. For example, it might have the ability to absorb and nullify the quirks of villains he comes into contact with. This would make for an exciting plot as he'd have to learn to control this new power and face the challenges of being seen as different by his peers.
I'm not sure specifically what that particular fanfiction is about as there could be many interpretations. It might be a story where Harry Potter has some unique heritage or magical property related to 'black blood' which could be a made - up concept in the fan - created world.
Izuku could develop by learning to accept his vampire quirk. At first, he might be scared or ashamed of it, but as he realizes the potential it has for good, he grows more confident. For example, when he saves someone using his vampire - enhanced abilities.
In the original Izuku story, his development is more traditional in the context of the hero world. But in 'izuku has the gamer fanfiction', he has gamer - like aspects. So, instead of just training in a normal way, he might be leveling up or getting new skills based on a game - like system.
Well, Todoroki is frequently paired with Izuku in such fanfictions. Given Todoroki's own powerful quirk and his journey of self - discovery, he and Izuku with his voice quirk can have some great interactions. They might train together, and Izuku could use his voice quirk to help Todoroki better control his own quirk's temperature aspects. Momo is another one. As a smart and resourceful character, she could help Izuku understand the scientific aspects of his voice quirk, like how sound waves work and how to optimize his quirk usage. And of course, Iida. Iida's strict sense of justice and leadership could pair well with Izuku. He might encourage Izuku to use his voice quirk for the greater good and help him come up with strategies to use it in hero work.
His relationships with his friends would likely become more complex. If he starts using his time quirk to change things, his friends might not remember the original timeline, but Izuku would. This could create a sense of isolation for him as he holds memories that no one else does.
His classmates could be his allies. They might be intrigued by his Pokemon - quirk and offer to help him train or use it better. For instance, Ochaco could use her zero - gravity quirk to assist Izuku in some Pokemon - quirk - related training exercises.
You could try looking on some popular fanfiction websites like Fanfiction.net or Archive of Our Own. Just search for the exact title or relevant keywords like 'Harry Potter' and 'black blood' to see if it pops up.