User blog comment:Ikmeos/Demonic power level, powerful weapons and the primordial siblings./@comment-91.89.184.182-20170228153932

The First Blade is the strongest weapons, Death's Scythe can only kill Death, monsters, demons and angels. It won't hurt Nephilims, human souls (Alistair did not use the Scythe to kill Sam and Dean when they were Ghosts in "Death takes a holiday"), ...