The Plasma scythe is an extremely powerful Yautja weapon. Used by Predator Vanguards, the Plasma Scythe can kill an enemy within four hits during gameplay. It is to be considered a force among forces, and is indeed powerful, but dangerous. Thus making it a weapon illegitimate for hunts.
Since the staff produces a blade made of high-heated plasma energy, it can burn through armor and enemies with ease. Upon creating a wound, it seals it over with the intense heat instantaneously, making it nearly impossible to heal the injury.