Cleansing this Essence will grant a piece of gear.
Get Grenade Launcher final blows in Vanguard, Gambit, or Crucible playlists, and claim the Bound Manacle in the Gatehouse to cleanse this Essence. Defeating Guardians grants the most efficient progress.
"To lose oneself to insanity is to lose all control over rationality. Some are forced into this path, others choose it. Beware those who elect this delusion—they pose the greatest threat." —Eris Morn