My Hero Academia took the anime world by storm with its new take on humans mutating. Unlike X-Men, the world of My Hero Academia shows a society that has accepted these superhumans. This change in social structure isn't surprising since more than 80% of the population has a power, referred to as quirks. The protagonist of this shonen is Izuku Midoriya, a young quirkless boy who receives the ultimate gift, One for All. While following Izuku's journey with his newly gifted work and hero classes, fans get to know Izuku's mom.
Inko Midoriya is Izuku's adorable mother, who cares deeply for her son. On more than one occasion, fans have seen Inko cry for her son's safety, stand up for him, and make him the first version of his super suit. Inko couldn't be more proud of her son, but she does carry such guilt since he wasn't born with a quirk. Both Inko and Izuku's father have quirks, Inko can levitate small objects towards her, and his father can breathe fire, but where is Izuku's dad?
What is Known
The manga has provided little information on Izuku's father. Fans know that his name is Hisashi Midoriya and that his quirk is fire breathing. It's assumed that Hishashi's fire-breathing quirk isn't as eye-catching as Dabi's flames since Inko brushed it off at Izuku's doctor's appointment as a child. Currently, Hisashi's work has taken him abroad, leaving Inko and Izuku alone. This is everything that's been revealed about Izuku's father, but what's interesting about all of this is that everything that is revealed about Hisashi was either from Inko or the creator Kohei Horikoshi.
From a story standpoint, not including Hisashi in Izuku's life meant that All Might could fill that father role, but why keep him as a character at all? Horikoshi could have made Inko a single mother or a widow. There would have been no need to include Hisashi unless he had a purpose. It can be assumed that Izuku doesn't know much about his father since he's never revealed any of the information about him, and what little he doesn't know wouldn't be enough for an identification. Kohei Horikoshi might have bigger plans for Hisashi Midoriya's character; maybe fans have already discovered this plan.
The All For One Theory
Fans and theorists have speculated over who Izuku's father could be. A popular theory is that Shigaraki, better known as All for One, is Izuku's father. The idea sounds like a stretch at first, but it's not as impossible after breaking down all the details and facts as some might think. First is that Shigaraki wouldn't have been injured until Izuku was about 8 or 9, meaning Inko could have met, fallen in love, and had a child with Shigaraki with no suspicion. If it also assumed that Izuku's father has always worked abroad, then Izuku wouldn't recognize Shigaraki as his father or be surprised that he was missing at all after the secret fight between them Shigaraki and All Might.
This isn't enough evidence, but fans recently pointed out that the doctor who told Izuku he was quirkless looks eerily similar to Kyudai Garaki. Kyudai is a mad scientist who is dedicated to Shigaraki, even making the Nomus for Shigaraki. It wouldn't make sense for Kyudai to casually become a doctor for kids, especially since his quirk has allowed him to live more than 100 years. Instead, Kyudai might have posed as a doctor for Shigaraki to ensure Izuku didn't have a quirk. Though, why would All for One care if Izuku had a quirk, especially if he received his mothers' gift?
All Part of the Plan
Shigaraki has dozens of stolen gifts, probably even more than that; there is a chance that Shigaraki has a gift similar to Nighteye's. If that's the case, Shigaraki might have planned to have Izuku, allowing Shigaraki the opportunity to steal One for All from Izuku. It would also explain why Izuku can access and see more of Yoichi, the original holder of One for All. The familial bond could be allowing Izuku to have more memories be revealed to him. Of course, fans know that not everything is set in stone when looking into the future. Izuku tends to change predetermined events, all to be a hero.
Then again, all of this could be wrong, and Shouto Todoroki might have been right. Izuku is All Might's secret love child, and Inko just isn't saying anything about it. This explains why Izuku can make All Might's vinegar stung face so well. It would certainly make those who want All Might and Inko to date happy. In the end, fans have to wait for the next chapter, or volumes, to discover who Izuku's father is and what he's been doing. He has years of parenting to catch up on, sort of like Darth Vader and his kids. Wait, isn't Kohei Horikoshi a massive fan of Star Wars?