I know that this isn't a Bleach or Fate oriented crossover, but other than this, and one more idea I might post at a later date that still isn't related to either of those two anime, I've mostly run dry of ideas. (I've already mentioned this before on a previous post, actually.) Thus, to get something out, I decided I'd post this.
This request is of an idea that I know hasn't been done before, so with that in mind, I'll start explaining what this request is about.
The main protagonist of the series "Classroom of the Elite", or "COTE", is a person known as Ayanokouji Kiyotaka. I won't go into details on who he is and what he is capable of, but basically he's really overpowered, whether it be physically or mentally, and he's highly skilled at manipulation. He is the "masterpiece" of a place known as the "White Room", and he is an unreliable narrator in his series. That's all you really need to know unless you go ahead with writing this request, in which case you'll obviously need to use preexisting knowledge of the character or do research into the character, if they are unknown to you.
I want this character, Ayanokouji Kiyotaka, to exist within the Toaru series. I do not want him to be transported there, like in an isekai, but rather I want him to have always been in that world. I still want the White Room to exist, but instead of it being headed by Ayanokouji's father, I want it be headed by people from the dark side of Academy City.
Our main character then escapes the facility at an earlier age then he does in "Classroom of the Elite" canon. This is so that he has a couple of years to adjust to society, and so that he isn't as of the mindset of "winning is everything", as he is in canon. (If you give him a strong esper ability, too, I'm not sure even the "invisible thing" would be enough to stop him, so this is a countermeasure.) You may give Ayanokouji his own esper ability if you so wish, or if you do not wish to do that, you could even make him a magician. Unlike in the story he came from, where it was nearly impossible to escape the grasp of the white room and he only managed to escape by going to an isolated-from-the-rest-of-the-world school, in this story, the heads of the "White Room" are not nearly so influential. As such, there should be no successful, or even close to successful, attempts at bringing him back, if you ever even make said attempts pop up at all in the story.
If you do plan to give Ayanokouji an esper ability, then read ahead. If not, this will likely not help you much. (Sorry if it seems like I'm biased towards that choice, but that's because I am.) I want Kiyotaka to be a level 5 that's unknown to the public, or anyone really, excluding the people at the "White Room". This all changes when he escapes the facility and undergoes a system scan. Following that, he's announced as a new level five. You can make him a gemstone if you want; it depends on what his esper ability is.
I also don't care what rank you give him in terms of the level 5's; power wise, he should definitely stand near the top, maybe even being stronger than Accelerator, but despite that, the rankings of the level 5's don't necessarily represent power level, so I can't give a definitive answer. (It more so represents usefulness to the schemes going on in the background of the city, from my understanding.) you can make him rank 4 at best, and rank 8 on the other end of the spectrum. I don't know what to make his esper ability, so you can come up with that yourself.
Another idea is to make Kiyotaka a level zero with no powers other than his fighting strength, physical prowess, and intelligence. Going with this idea, there is no need to cut back on his true personality and to make him less seeing-people-as-tools-oriented. I'd still want to make him have a couple of years to adjust to society, however. No matter what you do with these Tory, make sure to have Ayanokouji stick out in some way to the rest of his peers, and have him showcase his true personality when annoyed, which should happen more often than it does in canon, so as to spice things up.
I want Kamijou Touma to also be a main character; switch back and forth between their perspectives. Have this all take place post the whole scene with the 8 dragons coming out of Imagine Breaker, and then you can make up your own plot. I certainly don't want you going into world war three from there, though I suppose I don't know enough about the canonical timeline of the Toaru series to be saying such things. On another note, don't have Kiyotaka be as socially inept, since he's experienced a couple of years in society, and that's about it.
Sorry if this seemed like a mess; I just wanted to get something out.