>>82110525NTA but it's not about overpowering, it's about outsmarting. Oni have raw strength and ferocity but a skilled human can fell one by proper utilization of tactics that don't rely on just smashing swords into each other like they're WH40K Orks having a Dakka measuring contest. There are openings, there's flatout out-maneuvering them, redirecting attacks, feints to CREATE openings, etc. Outlasting is a no-go due to their vigor and stamina
(FOR SEX) but you aren't doomed just due to a race difference as long as you don't try to facetank/block a strike.