History of Conqueror for the Lost

Conqueror for the Lost is a Season of the Lost triumph toward the Realmwalker seal (Realmwalker): defeat bosses in Astral Alignment while wearing at least four pieces of the Pathfinder armor set.

How to complete

1. Get four Pathfinder pieces. The set drops from Astral Alignment, Shattered Realm activities and Umbral Engrams (Destinypedia, TheGamer).
2. Equip four or more pieces before launching. Astral Alignment is a six-player activity in the Dreaming City, recommended 1300 Power.
3. Run Astral Alignment: charge the compass, collapse Taken rifts to find beacons, retrieve the compass, then kill the final boss, Kholks, Taken of Xivu Arath or Kruutiks, Reefbane. The triumph names these two (Shacknews, Destinypedia). The mid-boss is Sulk'oth.
4. Defeat bosses with the armor on. The required count is not given in the sources I opened.

Rewards

Triumph score 20, counting toward Realmwalker.