The Sword of Plun-Darr is a double-bladed sword with a snake handle which can shrink into its handle when not in use. It can create fires, whirlwinds and shoot fire balls at its target.

When Ratilla tried to steal the Treasure of Thundera, Jaga stopped him using the Sword of Omens. The Sword of Plun-Darr was cast into the deepest canyon on Thundera by Jaga. Encased within the molten core of the planet, the Sword fought to free itself for years. Eventually, it caused a chain reaction which led to Thundera's destruction.

Years later when the planet began to reform, Mumm-Ra endeavored to retrieve the sword which was thought lost. The Sword was granted to him after beseeching the Ancient Spirits of Evil for it's ownership and power.