In this request, I want Ichigo to have decided to retire after the events of TYBW. The shinigami respect his decision, and they move on with their duties. Ichigo moves to go New York to have a fresh start on life, when suddenly he starts hearing things about various "super heroes" and wonders what's going on. Eventually, while living his life as a doctor, Ichigo runs into Nick Fury. Fury can sense that something about Ichigo is different, and that he looks trained in combat of some kind. Eventually, during the battle with the Chatauri, (I don't know if I'm spelling that correctly), Ichigo joins the battle in the background to minimize causalities, all while keeping out of sight of the Avengers so as to not be drawn into their affairs. The various Avengers all respectively meet Ichigo at different times after the battle, excluding Thor. They end up talking about him one day during lunch, and they also decide to look into the information they can find on him. They find that he went to school in Karakura Town, was seen as a delinquent due to his orange hair, fought a lot with various thugs harassing him for said hair, and that despite him missing a lot of school for some reason, he seemed to have gotten overall good grades. (You could also say that he had exceptional grades, and go that way if you want.) They find nothing to explain his seemingly good combat prowess, which they all find suspicious. You can make Ichigo whatever age you want in this, as long as he's not too young. I don't want him to be a teenager in this request, so maybe just make him the same age he was at in the epilogue of Bleach, or a bit older/younger than that. Put whatever age you give Ichigo in the information that the Avengers find on him. Anyway, the Avengers decide to have Ichigo be investigated, but they find nothing out of the ordinary, as he's just living his life as a doctor. That is, until Thor meets him one day. Thor immediately realizes he's a shinigami, but that there's also two more powers that seem to reside within him. These powers are later identified by Thor as quincy and hollow abilities. Normally Ichigo's quincy abilities wouldn't be detectable since he hasn't trained them, but in this request I want Ichigo to have trained his quincy abilities following TYBW, and thus he is even stronger in this story than by the end of that arc, and he still has all of his powers intact. Once Thor realizes Ichigo's true nature, he is told by Ichigo to not disclose who he is to the other Avengers, or anyone for that matter, and is told the truth about how he just wants to live his life as a doctor in peace. Have him have some encounters with the Avengers following their battle with Ultron, and then there should then be a major time skip. At this point, you can add other characters from the Marvel comics, or from the various TV shows/movies that aren't officially part of the Marvel movie universe, and have them be apart of the cast of this story. Have everyone mobilize to defeat Thanos, and have the story go pretty much how it does in movie canon, but with more characters and fights and such. Once Thor shows up as he does in movie canon, he makes a quick call to Ichigo, alerting him to the knowledge that the Avengers need his help. He arrives shortly afterwards, having brought his friends to help, who have also been training their powers the last couple of years following TYBW. This also includes Kisuke, Isshin, and Yoruichi. There are several meaningful interactions with the Blesch cast and the Marvel heroes, and the battle in Wakanda in general goes far more smoothly thanks to Thor and Ichigo. Here is where things start to differ from movie canon further: Dr.Strange doesn't give up the time stone to Thanos, as it is not necessary to win in this timeline. They manage to escape back to Earth, and the process of how they do that can be left up to whoever does this request. Thor still doesn't aim for the head of Thanos, but fortunately Ichigo finishes him off before he can do the snap. Vision is revived later, fully intact, and does not die after having the stone ripped out of his head. From there, the battle with Thanos is over, and the events of Endgame do not occur. Have the Marvel heroes go back to what they were doing prior to Thanos, and have the Avengers invite Ichigo to join them. Ichigo wants to refuse, but he can't deny how bored he and his two inner world spirits have been since he retired, especially in the case of Hollow Zangetsu. He's reminded of the time he lost his powers after the battle with Aizen, and so he decides to join them, but only if he can still work as a doctor on the side. Soul society is informed of what happened, and that Ichigo is going to join the Avengers, and they agree with it on the terms that no one else other than the Avengers or other superheroes can know that his powers are that of a shinigami. Orihime joins the Avengers as well, but Chad and Uryuu decide to continue their regular lives and help out if needed. Kisuke decides to set up shop in New York, and Yoruichi comes with him. Isshin remains in Karakura with Yuzu and Karin, who are significantly older at this point in the story, and they themselves are training their powers. They will not become as strong as Ichigo, however, because they are not being taught by Kisuke and they are not under the same perilous circumstances that Ichigo was under. Some shinigami visit Ichigo ever now and then, such as Rukia and Renji, who get together as per canon. After that, you can do whatever you'd like with this story; you can end it there, or you can have it continue past the point of the Marvel movies and make up your own plot.
Seems this length is slowly becoming the new normal for me, so I apologize if you’re not into reading such long paragraphs of text for just a request.
I’m still hoping that despite how fleshed out some of these are, that they can gain some traction and actually come to fruition, so if you are a writer, please at least consider doing one of these requests if you can.