Why isn't Yuder using a sword? Back home he's always training with a sword. But then when he goes to battle, he's always punching with his fists, ineffectively.
Why isn't Cordelia drinking mana potions? When they conquered the dungeon in the library, she was drinking those, complaining they fill her stomach too fast. But now she wouldn't drink even a single one.
I fear this is written by one of the authors who don't care about consistency. They only write every fight to suit the current needs of the story, without minding the details at all.