Ken_Kaneki_UWU
If you want some universes to shove your mc into, I think that the original Jojo universe is one of the best along with maybe Jujutsu Kaisen or RWBY. Don’t sweat it, I tried putting D4C into worlds and I failed too in my fic
FPJK:Also a recommendation is that the mc only has D4C and not any other main character powers. This is because it wouldn’t be funny Valentine enough due to the fact D4C isn’t taking the spotlight.
Yeah you mix DxD and Jojo universe is not good in my opinion, if you want to combine them you need to change the DxD and Jojo world history. if you want a mix Jojo universe wirh other anime i suggest maybe Persona anime or game since their ability is similiar. then you can travel to other universe instead combine them