Obsidian Doom

Obsidian Doom is an obsidian sword with powerful magical properties, including the ability to permanently kill a wizard. It was forged by the Necromancer Dripfang LeDesparé

+ Warning! Spoilers Inside for Season Three. Click to reveal

Dripfang created the weapon using a variety of magical artifacts stolen from The Jizzlenob Preparatory School For Young Wizards. His plan was to win the the Dark Lord's favor by killing the wizard Usidore, but the blade instead ended up embedded in Arnie Niekamp nearly killing him.¹

Its magical nature makes it unsafe to remove the blade even after Arnie's condition is stabilized, so blade stays embedded in Arnie's chest for almost a year until it is separated from him during a time travel experience. The blade now free and available to use against the Dark Lord, Chunt suggests they rename the blade Usidore's Hand, in reference to the period in which Usidore's hand had turned to stone.²

Besides the power to permanently kill a wizard, the sword can also cut through the crystalline barriers that appeared throughout Foon as a result of The Shattering.

Footnotes

1. Season 3, Ep 21 – "The Lurking Phantom"

2. Season 3, Ep 70 - "Arnor's Next Feat"