Hell of a thing., isn't it? I mean, Genghis Khan not having that all-time mass murder prize isn't due to any lack of effort on his part.
Likewise, Tamerlane wanted that trophy really bad, and tried really hard:
but that all-time mass murder trophy still went to a shit4brains idiot leftwing female yuppy on a crusade against DDT which cost the lives of something like 100,000,000 people :
Rachel Carson: All-time prize for mass murder.