The title is essentially my question. I have heard the weapon called that before, but i am curious as to both the why, and as to the origin of this term and the concept of the weapon.
A Scythe is a 2d4 damage weapon.
A brutal weapon asks you to reroll damage dice that are equal or lower in number to the weapon's brutal rating.
So a Brutal 3 Scythe automatically deals 8 damage on a hit. (As each d4 is rerolled until a 4 appears)
Make it Vorpal (L30 enchantment)
Whenever you roll the maximum result on any damage die for this weapon, roll that die again and add the additional result to the damage total. If a reroll results in another maximum damage result, roll it again and keep adding
And your Brutal 3 Vorpal Scythe does infinite damage on every hit.
So every hit is an auto kill (barring any defensive funkyness) and so is a weapon worth of being weilded by Death