
Originally Posted by
Xurts
Kill 2 of your party members before you enter the battle so Ruby's Whirlsand attack takes them out of the battle. Have your last character summon KOTR. It won't do any damage, but it will make Ruby stick his tentacles into the ground. This makes him vulnerable to attacks now. W-Summon KOTR and keep Miming that until Ruby dies. Of course, it's a good idea to have KOTR mastered so you get maximum damage. Linking MP Absorb, HP Absorb, and/or MP Turbo with KOTR and Master Summon would be a very good idea.
Here's the materia combination that I used:
Wpn - MP Turbo = Master Summon, W-Summon, Mime, Master Summon = HP Absorb, MP Absorb = KOTR
Arm - Final Attack = Phoenix, W-Item
The only downside to this strategy is that KOTR's summon sequence takes so blasted long. There is pretty much no way that you can lose with this setup, since if you die Phoenix will revive you.
You can also use Lucky 7s and Mime a bunch of multi-hitting Limit Breaks like Omnislash. Another way to do it would be to feed Barret a bunch of Hero Drinks and have him Mime Ungarmax.
A much better strategy, in my opinion, is to use W-Summon, Hades(linked to 4X) KOTR (linked to HP Absorb), and counter/mime.
If you have a master summon, swap it out for either (or both, if you have them) Summon materia. You get the same effect.
What this does is Poisons and freezes the tentacles, and freezes ruby so it cannot counterattack you after a KOTR. And if it does, then you'll just hit it again with the counter/mime of your last action and heal the HP it took away. If you can set the controller to memory and tape down the button, you can actually win without even watching the fight.
Addendum: And yes, make sure your party members are KOd before the fight starts.