Can be found in Shadow's Edge in the time of past.
|“|| Forged in a blast furnace by the demon lord Belial, the Demonflame Renders flare with hellish heat and flame that causes enemies to explode into flames with every strike. Originally meant to serve as a gift to secure favors from Lilith, the Renders were stolen by one of Belial's many rivals... or so he claimed. Whatever the truth, the scythes disappeared for an age, lost or secreted away. The merchant Ostegoth claims that the scythes are loose, seeking out a new and more worthy owner - perhaps these weapons are possessed of a similar hubris to the Demon Lord who created them.|
— In-Game Description, Darksiders II