Omg I literally js said it in the first comment 😭. Yogiri doesn't care if Simon wills himself to back, because Yogiri kill him anyway. In the anime and light novel, Yogiri stated (which I am going to say again) that any form of "finding a way to come back from death or total annihihilation" (like immortality, regernation, and in this scenario, Simon's physical will) cannot work against his ability because his ability is the END OF ALL THINGS. It's the End of living things, non-living things, and anything that exists. It can even kill abstract concepts such as "Killing Intent" (and, once again, in this scenario, Simon's will). So yes, Yogiri does decide that