Idk if this has been done before but Soul Eater au where Fushimi is a witch either like Kim or Angela and has to be protected by (depending on the scenario) his weapon partner Yata or by master swordsman Munakata. Really I think either would suit Fushimi because both backstories are very sad but with happy endings
So Fushimi is like the Monkey Witch (sorry Saru) and he’s always been hated and persecuted by the other witches for his strong powers. Maybe it’s not even the witch community at large that really persecuted him though, like his father Niki was one of the strongest witches and was hated even amongst his own kind because Niki would never even work with the other witches and often would do things that caused other witches to be harmed or even killed. Niki made certain Fushimi knew that no one in the world was his ally, that even the other witches would destroy him if they could and that there’s basically no one in the world that Fushimi can trust. Eventually Niki is hunted down and killed by a group of witches who then go looking for Fushimi, not wanting to let him grow up powerful like his father. Fushimi just manages to escape and lives all by himself scraping by for food when one day Munakata, the scythe-wielding headmaster of Shizume Weapons Academy, stumbles upon him and offers to let him join the school as a student. Only Munakata knows that Fushimi is really a witch and even though Fushimi doesn’t trust Munakata he still takes the offer because he has nowhere else to go.
After that Fushimi begins living in the dorms but he’s standoffish towards all the other students and refuses to hang out with anyone or make any friends. Even though he’s ostensibly there as a meister he makes no moves towards teaming up with a weapon of his own and basically shuns everyone, believing that even if he did make a friend it wouldn’t matter because he’ll be abandoned the moment someone finds out he’s a witch. That’s when he runs into new student Yata Misaki one day when he’s skipping class, Fushimi’s hiding in the bathroom playing on his PDA and Yata shows up not expecting to see someone else there. Yata as it happens isn’t fitting in well in school either and as a weapon he’s frustrated that no meister seems to be able to wield him, Fushimi just clicks his tongue and states that it’s none of his business and Yata should just go away. The next day though maybe Fushimi’s out in town and a witch who sneaked into the city confronts him, Fushimi’s trying to figure out how to handle this without having to use his powers when Yata comes barreling in to save him, believing that a witch is just attacking poor innocent Saruhiko. Yata ends up turning into his weapon form, a saber, and Fushimi uses him to defeat the witch. Afterward Yata can’t stop talking about how awesome Fushimi is and what a great team they made and Fushimi almost finds himself agreeing.
The two of them eventually end up becoming friends, Yata not allowing Fushimi to sink back into his solitude and constantly checking up on him and taking care of him when he’s sick and together they make a great team. Fushimi almost starts to think that maybe he can do this, he can belong at someone’s side, until there’s this big situation involving the witch Colorless who’s trying to like revive the ancient hidden weapon known as Damocles which could destroy everyone on the planet. Other witches are working with Colorless and when Fushimi and Yata are dispatched along with the rest of the students to fight the witches of jungle threaten to blackmail Fushimi, noting that even his comrades don’t know his true self and wouldn’t Yata turn on him and kill him if Yata found out. Trapped and feeling like he will lose everything at this rate Fushimi seemingly betrays the school to join the side of the witches, until Yata comes after him. Fushimi assumes that Yata doesn’t know he’s a witch and starts mocking him about it, like there’s been a witch in your midst all this time Misaki and you didn’t know it. Yata stands his ground though, stating that he did know it – when their souls resonated together he was able to see that Fushimi’s was the soul of a witch but he never said anything because he believes in Fushimi and he’s always believed in Fushimi, that even if he’s a witch Fushimi is still the coolest guy Yata’s ever known and Yata believes in him, that Fushimi is on his side and that Fushimi is still his partner no matter what.