ALLLLLLRIGHT, I just got to around to reading your fanfic. I have to say, it's definitely gotten a great story so far. I'm not judging based on spelling errors or mistakes (Being that 1. it's clearly understandable and 2. I'm sure I have some mistakes as well here and there), only the content and the other pieces itself. I would try and strive more towards going in your own direction with some things, I've noticed that you sometimes go with the MHA Anime/Manga and parallel it to Daiki and the others. Which honestly, isn't really a bad thing, it's always good to start somewhere and have a stable build up, even if you have to use some things from the story.
The characters could use a little work, by that I mean have some chapters where you could possibly have them interact more with Daiki outside of the whole U.A. High setting (Exams, Fights, and such). Feel free to put your own spin on Daiki as well, do things that you haven't seen any other MHA Fanfic OC do yet! Another thing, I highly encourage that you don't use "Said" as often, unless need be of course, that way it can spice up your chapters! Again, I really would like to see more from some of the characters that are the most important besides Daiki! You've gotten quite a bit, but you've opened the surface on some really awesome character development for these characters.
Also, don't be afraid to bring new things to the table! As long as you build them up and have them make sense, it'll go perfectly with your story! For example, the Tanjiro being Leonidus' Great Grandfather in my story, that shouldn't have made sense but having moments outside of the character helped it come together. I'd also recommend that you go back through previous chapters once you have the time and combine some of the sentences with each other, having paragraphs at LEAST 6 to 7 sentences (That aren't filled with action/fighting, then really about 10 to maybe even 12 are acceptable) makes it a bit easier for people to read. Speaking of that, also separating your spoken dialogue from the written dialogue helps out as well!
All in all, this story has the potential to be amazing! I honestly love the direction you're going so far, but I really do recommend that you have fun with it, test things out that people may like or that people might not like. Take criticism (Like, actual well thought out, not like "Oh, this sucks, make this a Harem" or "Garbage... Daiki needs to be this and this..." and so on) and use it to improve your story as well. As long as that criticism is valuable, actually pointing out flaws instead of calling it garbage and leaving it at that, you can use that to your upmost advantage. And the obvious, go through your chapters and correct spelling mistakes and what not. Other than that, I personally love this story so far and can't wait to see where you take this! Keep on writing, don't push yourself to put out chapters everyday either, just go at your own pace!
