Omega Ruins

The Omega Ruins are unlocked via the Airship Secret Locations sidequest. Once you have unlocked it you can enter and attempt to complete it. This is perhaps the hardest area in the game, so make sure you are well prepared.

The first part of the dungeon is a maze of tunnels with various rooms with treasure chests scattered throughout. It doesn't matter what order you open the chests in, you will always receive these prizes in this order:

  1. Lv. 4 Key Sphere
  2. Defending Bracer
  3. Turnover
  4. Lv. 3 Key Sphere x2
  5. Defending Armlet
  6. Friend Sphere
  7. Lv. 4 Key Sphere
  8. Phantom Ring
  9. Cactuar Wizard
  10. Warmonger
  11. Teleport Sphere x2
  12. Warp Sphere x99

Sometimes when you open a chest, instead of the prize you'll have to fight a battle with a Mimic (A)/ Mimic (B)/Mimic (C)/Mimic (D) and a Zaurus. If that happens or if you save, or leave the dungeon, the chest prizes will start over again from the beginning.

In the rear left of the dungeon is a room where you'll find the Al Bhed Primer XXVI lying on the ground near the back.

Towards the rear right of the dungeon is a room with a floor seal surrounded by pillars. When you enter this room, you'll have to fight Ultima Weapon.

After beating Ultima Weapon, you'll be transported to to a new section. Each time you come to a circular area, you'll enter a battle. Go to the left to fight Gemini (A) and Gemini (B) then 2 Wraiths to get a Friend Sphere.

Go back and head right. The battles are fixed in this order: Varuna, Adamantoise, Master Tonberry, 2 Defender Zs, 2 Demonoliths, 2 Demonolith, 2 Wraiths. After those battles, head north to fight Omega Weapon.

After defeating Omega Weapon leave the cave and then return to where you fought it to pick up a Magic Sphere.

Armor: Weapons: Items: Key Items: Enemies:
Notes: For strategies on how to obtain all of the prizes on the first level, you'll need to read this guide on GameFAQs.com: Omega Ruins FAQ