Comment by Cat._. on My School Life Pretending To Be a Worthless Person - Chapter 33

I think it's because he only turned on his edeya for his right hand

he "separated" (???) a part of his edeya and he can use it only in one hand without activating the whole thing, so only a part of his edeya is A-, the overall is still S

Because its "partial murder" so because he can still control it its lower grade

Reading the replies and yeah it really makes sense tbh, he only used his right hand so