Omega Ruins

The Omega Ruins, also known as Omega Dungeon in the menu at the Monster Arena, is a large optional dungeon located within a small group of islands to the east of Spira's main continent in Final Fantasy X. Rather maze-like, like Inside Sin, this place must be mapped by the player. Navigating the dark passages, Tidus and his friends will encounter some of the toughest fiends, including the Master Tonberry and Great Malboro, while also coming across chests, which yield some handy treasures.
At the end of the cave, two deadly bosses await the party's arrival.
A traitor to Yevon, Omega, was executed for treason centuries ago, his malicious spirit still haunting these ruins. His hatred has turned him into the fiendish Omega Weapon. His hatred for Yevon was so strong, he also spawned a lesser Weapon: Ultima.
== Coordinates ==
To be unlocked on the airship map, the coordinates 69-75x and 33-38y have to be found using the search function.
== Items ==
=== Treasure minigame ===
There is a secret minigame involving the four groups of treasure chests in the ruins. These chests randomly contain either a treasure or a Mimic. If one opens a Mimic chest, the other chests in the same chest group disappear. If one opens a chest but leaves the chest group, the other chests will disappear even if the Mimic did not appear. Chests that have disappeared will not reappear after leaving and re-entering Omega Ruins, and so this minigame can only be played once per save file. The goal is to open all chests in all four groups without opening a Mimic chest to earn 99 Warp Spheres from the final chest.
Each group of chests has equal odds for each of the treasure chests to contain a Mimic or for there to be no Mimic at all with the constraint that there can at most be one Mimic in a chest group. E.g. the group closest to the entrance has equal odds that the left chest contains a Mimic, that the right chest contains a Mimic, or that neither contains a Mimic. This means that there is a 1/3*1/4*1/4*1/5= 1/240 chance of all chest groups having no Mimics.
In the PlayStation 2 versions, the configuration is determined each time the console loads the Omega Ruins based on an RNG ("random number generator"). Whether an opened chest is a treasure or a Mimic has nothing to do with the timing of the music or the order in which they are opened. Whether success is possible at all is not set in stone from the first time one enters the ruins. The output of the RNG function changes from load to load, so the most effective way to obtain the spheres is to make a save at the start of the dungeon and soft reset and reload until a perfect run. 
Loading a saved game with any of the chests open resets the prize counter, and the player still needs to open all 12 chests in a row to get the 99 Warp Spheres. However, because opening a chest or group of chests causes the group to disappear, saving and loading the game between groups leads to fewer than 12 chests being available and thus renders the 99 Warp Spheres prize unachievable. Saving the game between groups without reloading does not reset the counter (i.e. opening 2 chests, saving, then opening the 3rd chest still gives Turnover as expected). This applies to the remasters as well.
The PlayStation 3 version yields unexpected results. While the configuration of the chests changes from load to load within a save file made in the Omega Ruins, each save file appears to be locked into switching between about 70 configurations, of which the winning configuration may or may not be one. There is as of yet no adequate explanation of this phenomenon.
The chests contain the following items:
# Lv. 4 Key Sphere
# Defending Bracer
# Turnover
# Lv. 3 Key Sphere x2
# Defending Armlet
# Friend Sphere x2
# Lv. 4 Key Sphere
# Phantom Ring
# Cactuar Wizard
# Warmonger
# Teleport Sphere x2
# Warp Sphere x99
=== Normal treasures ===
* Al Bhed Primer vol. XXVI (near last four treasure chests)
* Teleport Sphere (activate the two glyphs)
* Friend Sphere
* Magic Sphere (return to where Omega Weapon was fought after his defeat)
It is recommended to use the diagram to get the Teleport Sphere by activating the glyphs. For that, the player must move to the west corridor from the entrance, follow the path up to a doormat glyph on the wall, head north to find a chamber with four chests, head northwest into a side corridor with another glyph, activate it, and return to the "doormat" one. The glyph is now working and it raises a bridge out to a chest suspended above the central stage.
== Enemies ==
* Lower part
**Zaurus, ???
** Zaurus, ??? (Ruminant Mimic {red life core})
** Zaurus, ??? (Mech Mimic {blue life core})
** Zaurus, ??? (Roc Mimic {yellow life core})
** Zaurus, ??? (Basilisk Mimic {blueish green life core})
** Zaurus x2, Floating Death
** Master Coeurl x2, Floating Death
** Black Element x2, Spirit
** Halma x2, Spirit
** Machea x2
** Puroboros x3
** Defender Z x2
** Adamantoise
** Wraith
** Demonolith x2
** Varuna
** Great Malboro (always Ambush battle)
** Master Tonberry
** Ultima Weapon (Boss)
* Upper part
** Before defeating Omega Weapon
*** Defender Z x2
*** Adamantoise
*** Demonolith x2
*** Varuna
*** Great Malboro (always Ambush battle)
*** Master Tonberry
*** Wraith x2, ???
*** Gemini (sword), Gemini (club)
*** Omega Weapon (Boss)
** After defeating Omega Weapon
*** Puroboros x3
*** Defender Z x2
*** Demonolith x2
*** Varuna
*** Great Malboro (always Ambush battle)
*** Master Tonberry
*** Gemini (sword), Gemini (club)
== Musical themes ==
The theme that plays in the exterior of the Omega Ruins is "Beyond the Darkness". "Gloom" plays while in the Ruins.
== Other appearances ==
=== Final Fantasy Airborne Brigade ===
== Gallery ==
Omega_Ruins_2.png|Omega Ruins.
FFX Omega's Chamber.png|Omega's Chamber.
es:Ruinas Omega
Category:Locations in Final Fantasy X
Category:Caves
Category:Ruins