Volendrung

Overview
Volendrung is a Top-Tier Longinus Class Sacred Gear, but was not actually created by God, but rather was created by a being more powerful and cunning than Him and then added his or her creation to the Sacred Gear System. No one knows who created Volendrung, but it is known to be more powerful than the True Longinus and is sometimes said to be its antithesis.

Appearance
Volendrung appears as a very large bronze war hammer with a glowing center, as well as several pale green runes blanketing the surface.

Abilities
Volendrung, while its abilities being initially unknown, is known for being able to bring complete and utter devastation. It is also said that it could destroy the entire Underworld in one swing. The only hint of its abilities is one of its many titles, The Spurn Star, thus Volendrung's power being theorized to revolve around curses and the spurned.

However, at the beginning of the fan fiction series Project New DxD, its abilities are discovered as time unfolds.

Summary
No one knows just who created such an instrument of mass destruction, and no one will ever know.