Let mc create in his personal team of people from different anime.
Izayoi sakamki power to destroy magic and opponents(super debuff) ability like vali divide and sending issei's boost back to reset.you could eaisly defeat him with physically if he did not have a hercules level physique
akatsuki kojou powerful vampire have familiars with different special ability(each one have potential of longinus )
Ragna the bloodedge (tons of abilites screah it up)
Cradis etrama d raizel his power cost his life force but mc system could help him.
FBIultimate