@KD: I think your worry about Senka is same sort of "selective blindness" as Sucroses worry about hurricanes
. Just like ordinary ceros are perfectly viable for leveling cities, there are ways for characters to permanently impair others that don't require anything special - fractured spines, lost limbs and brain damage are all possibilities, and not trivial to many characters.
As others have pointed out, this is a community effort and
all injuries are contingent on mutual agreement. Senka is nothing special in this regard - it's just one thing more on a list that's already very long.