VIDEOS:
The Ashen Demon
Byleth Eisner, renowned as the Ashen Demon for their skill on the battlefield and lack of emotion, single-handedly decimates Berling's Mercenaries and demonstrates why Shez wasn't in Three Houses, who can barely scratch them. For the rest of Three Hopes, your best option is to simply not fight them.
Example of:
Curb-Stomp Battle