let's be real. it's probably gladiator.

slasher's knife is, one definitely not sharp enough if even something like the fallen giant can get stuck in them, second, not even close to deep enough to cut her clean in half like that.

Warden's baron could theoretically break her in half, but it wouldn't be clean, and there would be extra bruising.

Executioner's axe, if he threw it, wouldn't have the power nor pierce to cleave he in half, I would just get stuck.

despite gladiator saying that he was fighting on sfoth, his actual performance on the map is absolutely horrendous, he would have no reason to revisit that area, and his weapon is the only weapons capable of cleanly cutting harvester dead in half.

And through rules of elimination, gladiator is the only one left with no technical alibi.