War Numen’s Oryx armor in Destiny 2 drops from the King’s Fall raid. The armor pieces are random raid drops, so the way to get the full set is to run King’s Fall repeatedly and clear the encounters that can award armor.

How to get it

  • Play the King’s Fall raid.
  • Complete raid encounters and loot chests.
  • Keep running the raid until the War Numen pieces drop; the set is not a guaranteed one-run unlock.

What to expect

  • The armor is tied to the Taken King / King’s Fall raid source.
  • Like most raid armor, the drop is RNG-based , so some players get pieces quickly and others need several clears.

Fastest approach

  1. Form a raid group.
  2. Clear King’s Fall encounters on the characters you want the armor for.
  3. Use multiple characters each week if you want more chances at drops.
  4. Repeat until you finish the set.

Extra note

If you meant the War Numen set for a specific class, the same answer applies: it still comes from King’s Fall, just the class-specific armor pool from that raid.

TL;DR

Run King’s Fall and farm raid encounters/chests until the War Numen armor pieces drop.