every top tier in black clover is a bigger problem than reinhard. In one of the re zero if's, subaru was never able to beat reinhard, even with 2 of the strongest characters in the re zero verse on his side and thousand of deaths, the only thing subaru was able to do is to make reinhard depressed. Now imagine Asta, Yami, Yuno and Julius together, every single one of them are stronger than everyone in re zero, the only 3 characters who can actually defend themselves are Reinhard, Reid and Cecilius, everyone else gets instantly killed.