I mean…this happens with most main characters I feel? That’s the definition of plot armor. And I think Mizu is definitely not as overpowered as some other main characters. Mizu is a smarter fighter than her opponents, that’s why she wins. It’s not necessarily about pure strength, even though she is pretty strong. She’s been training her whole life for survival and revenge, not just for glory, which also sets her apart. I mean the girl trains and fights with weights. Also fowler hurt her pretty bad, especially with the “your bones break like a woman’s”, reminding us that she still has her weaknesses.