Willbreaker

Willbreaker is the sword of Oryx, the Taken King. He used it to slay Akka, the Worm of Secrets, and to carve the Tablets of Ruin from its flesh. Its shards later scattered across the Ascendant Plane, and some were recovered by other factions.

In Episode: Heresy, Eris Morn tasks the Guardian with gathering the shards to reforge it. At least three shards are needed, and extra shards make the reforging easier. The shards are fused at a reforging ritual at the Court of Blades on the Dreadnaught. The reforged blade can cut open rifts into the Ascendant Plane, which helps free Eris from the High Heresy.

The reforged sword is later used against the Echo of Navigation.