Gorshalach

History
Gorshalach, (the Dark Render) is the most powerful weapon in the universe. This massive greatsword was originally wielded by Sargeras while he was a member of the Titan Pantheon. When Sargeras fell to his madness, Gorshalach, being semi-sentient, sundered itself into two 'Shatterbound pieces' to prevent the fallen Titan from wielding it. One fragment was claimed by Sargeras and reforged into Gorribal, while the other was claimed by Aggramar and reforged into Taeshalach. If both fragments are ever possessed by a non-evil being, they can be combined to reform Gorshalach.

The Rains of Vamir
The sword was fused back together by Vamir during his assult on Azeroth, which gave him the ability to destory everything