Another thing you could do is reveal Yuroichi's zanpakuto even if you create it yourself it doesnt matter because she is also a shinigami and zanpakuto whill have great impact on her character development
7 deadly sins could also be a good choice for Jaina's character development and Saber's especially if they meet Merlin and Arthur and its interesting to see because there is also demon faction, human faction and god faction there
BTW I should think that you should reforge ICHIGO's ZANPAKUTO especially that he doesnt only have quincy/hollow and shinigami power anymore but also demonic energy this means you can make it into a new blade when activating his shikai making it three especially when reincarnating into a demon there must have been changes happening into his soul and you can introuduce a new character for his sword spirit like Phoenix especially that he is part of the Phenex clan same for the other shinigamis
Make the MC also have another peerage and that would be awesome a reason you could give is his soul can handle it because I want another set of peerages
Dear god no SAO. If you have to use a pre transformation Overlord, or Log Horizon. But no SAO unless it's got them beating the crap out of that dipshit MC. Or not interacting with them at all.
They never heard of the saying "the path to hell is paved with good intentions"? So what if he was good, he was misguided and wanted to start a war. A ware between the three faction, who would suffer the most? The humans in the middle, earth where there will actually happened.
You gotta have ichigo permanently fiuse dangerous and the old man together, making his true spirit. Once he has done that, he can re-establish the soul society, giving humanity ******* from servitude to various gods. After that, they can go to Hunter x Hunter, learn nen, and then teach it's principals to the rest of humanity, serving kokabiels goal.
IdleWolf07