Final Fantasy X Fiend Capturing Episode 5: Capturing in the Omega Ruins

Hello all, and welcome to my Final Fantasy X guide! This is the fifth episode which focuses on the capturing aspect of the game. Capturing is very important because you need 10 of every creature to unlock Nemesis, and you also get some fantastic rewards for capturing various groups of monsters. I would strongly recommend that you use an app to keep track of how many of each fiend you have captured. I used 'Checklist for FFX' on Android.
**THIS WALKTHROUGH CONTAINS SPOILERS THROUGHOUT**
This episode focuses on the Omega Ruins area, which has the most powerful regular monsters of any area in the game, but correspondingly is the best place to gain some S-levels as well. If you have the spare cash before entering the ruins then it can be convenient to customize a 4 slot weapon (bought from Wantz) with Darktouch and Silencetouch, and then add Darkstrike and Silencestrike afterwards. If you can only use one of Silence or Dark, go with Silence.
Since your endgame perfect armour is going to be Auto-Haste, Auto-Protect, Auto-Phoenix and either Stoneproof or Ribbon it is a good idea to customize a 4 slot armour for someone. If you're only going to get Ribbon on one character's armour for the Dark Aeons (see my video on Endgame Choices Discussion for more info) then putting Stoneproof on there is a great help too. At least one character needs some sort of Stoneproof armour whilst you're in the Omega Ruins, and if you can have a main party member with Confuseproof/Berserk Ward then that it helpful too.
Always, always, ALWAYS have First Strike with someone in your front line party. I have Tidus with First Strike-Capture. Great Marlboro automatically ambush you and use Bad Breath in the Omega Ruins (ignoring Initiative even if you have it) and you DO NOT want Bad Breath confusing and berserking your whole party, especially with Poison on top to boot. It's an easy game over unless you get lucky. ALWAYS Provoke Great Marlboro and then keep that character in the battle for every turn Marlboro gets. If you can't Provoke, then use Delay Attack or Delay Buster (it'll counter with a damaging attack), Flee, or switch in Yuna and summon an Aeon immediately.
The fiend Spirit (floating triangular head type fiend) has a deadly Poison Must attack that it can use either on its turn or as a counter. Always Provoke this enemy too.
A useful technique to learn to save yourself some time in this area is using Rikku's Black Hole Mix overdrive. If you collect your capturing rewards for the other areas first, you'll have 99 Shadow Gems and 99 Gambler's Spirit. Mixing these two items gives the Black Hole overdrive which deals 93.75% of a fiend's health unless they are immune to Gravity attacks.
This is a fantastic tool for quickly stripping high health enemies like Great Marlboro and Master Tonberry if you have Break Damage Limit on Rikku's weapon. You should also DEFINITELY complete the Village of the Cactuars sidequest and fully upgrade Rikku's Celestial weapon Godhand. This gives the Break Damage Limit ability that is required, but crucially also has Triple Overdrive. Set Rikku's overdrive mode to 'Victor' and when she is holding this weapon she will get 60% of her overdrive gauge filled just for being in the front line at the end of the fight! As shown in the video, this can end battles very quickly even against these extremely high HP enemies whilst still allowing you to capture them.
The enemy called Demonolith are also dangerous. They can use their all-party attack that has a high chance to petrify all characters even when they're Silenced, so always have someone with Stoneproof in battle if they get a turn. They also have a nasty Pharoah's Curse counterattack which causes Darkness/Silence/Curse/Poison. Silencing them stops this however, so use either a Silencetouch+Silencestrike weapon, Silence Buster or a Silence Grenade (stolen from Exoray or other mushrooms) as your first attack against them. They have 45k HP so 5 attacks will see them defeated and captured if you armour break them; you fight them in pairs in the Omega Ruins so Silencing both and then using Black Hole is the way to go.
There are two bosses (Ultima Weapon and Omega Weapon) in the ruins. Ultima is a pushover, but you can bribe Pendulums for a massive amount of Gil if you wish. Omega has 999,999 HP so can take a little while, but otherwise isn't too tough. Kimahri should use Lancet to learn Nova from him.
After Omega Weapon is defeated, there are only 7 combinations of fiends that you can encounter in that area with the circular platforms and two of them are Varuna and Master Tonberry,
WALKTHROUGH SUMMARY
The description of this episode is too long, ha! Please see the previous episode for the walkthrough mini-summary!