I'm not exactly sure how this would work, but it is an idea that came to mind. Recently I've begun to lose a lot of my interest in the Fate Franchise, however one thing that remains consistent in my like of the series is that I heavily appreciate the character of EMIYA, also known as Archer or Counter Guardian EMIYA. I don't particularly care for a regular DxD and Fate crossover right now, but a fan fiction that inserts EMIYA into a combined world of DxD and Bleach would be quite interesting in my opinion. Have the three main characters consist of Issei, Ichigo, and EMIYA himself, or just Ichigo and EMIYA since I don't really care much for Issei. Maybe have Ichigo's heroic/protective tendencies remind EMIYA of himself, and branch off of that or something to create a conflict outside of the general DxD storyline, and have some stuff like that or just interactions in general scattered throughout the story. I don't know what my opinion on romance in the story is, but I suppose as long as there isn't too much of it would be fine with me. Have Ichigo be post TYBW, with true Bankai, EMIYA be pre Unlimited Blade Works, and if you include Issei, have him be pre canon.