ya so in my 7 yrs of being an izaya fan i've obv got into different things as well. the biggest crossover i am still invested in to this day is my izaya p5 au.
this is his confidant screen btw. ♡ i've also written an "essay" on how his palace would be like. it's really messy and all over the place but once i clean it up and make it cute it'll be here.
i dont have any real cool crossover stuff to put here bc genshin is a lot more annoying to edit stuff with but i think he'd be a catalyst user!!! and of course electro...
in terms of kit? i feel like his attacks would be similar to um this is not intentional at all but scaramouche... but instead of anemo blades he'd throw knives... honestly i think he'd be something similar to a ranged dps but the bow just doesn't fit him so...
for his elemental skill i havw this image of like... a huge formation of knives that just fly towards the enemy... OH or something similar to one of his skills in crossing void where he like. dashes forward and slashes them repeatedly. idk maybe the first thing could be his burst or smth i'm not good at making kits LOL