History of Soulfire Rancor

Soulfire Rancor is a Cull's Shadow catalyst. It is the reward from the chest at the end of Oblation: Soulfed, one of the three Oblation missions on the Moon.

The chest may not spawn if the boss is killed too quickly, so complete the worm-throwing and detonation steps before the final blow. Guides describe its effect differently, so check the in-game perk text.