An easy way to defeat him is to use Kuja. Basically have Kuja at level 100 and make sure you have the hp attack ultima equipped and have good level 100 gear such as the lufenian gear. Fly as high in the arena as you can by doing dodges and stay up there. Now from this height just spam Ultima. It will take time to kill him seeing as he has 120k hp but Feral Chaos has no air game at all and if you just keep spamming it you will remain untouched. I beat Feral Chaos using just Kuja believe me it works.
Theres no specific people you have to choose. Just choose the three people your best with. For me it was Cloud, Firion, and Laguna. Then when the battle begins be sure to get away or land the first strike. Have one person equip with Magic Pot and another equipped with the Level 5 death summon thing. Be sure to use your characters from worst to best. Save your best person for last. Trust Me! Learn when and how he strikes. Do NOT get mad and throw your PSP bc that does not help!
1. Ok so make it your bonus day for extra exp. 2. Then if you have enough points buy exp X whatever. The most is two. 3. Then have your play plan thing on exp X5. In order to do this you simply just hsve to do battles, and eventually a chocobo will show up. Open up your edit screen to check what you got. 4. Then after this equip whomever you choose with Magic Pot. 5. Then fight Gabranth LV.100 6. Let him keep hitting you till his brave reaches 9999. 7. Activate Magic Pot. 8. Finish him off and WOW! You got plenty of exp.
This hint is avaliable to any level, equip chocobo down, then face against enemy maximum state. Ususally it give you boost EXP, you can also finish with Ex Burst for bonus EXP and I also recommend it. My lightning level up from level 22-40 in 15 minutes
To learn Finishing Touch simply get the bravery attack sonic break and master. For this one you need 120 AP. Then simply go to your abilities and equip it. It will be below sonic break in your abilities. Once again to do this use sonis break then just keep pressing square.
In order to do this you need to have Cloud's bravery ability Slashing Blow, then Master it.In which You need 220 AP to master this. Then after you master go to your abilities and go down to slashing blow. You should see omnislash V.5 chained to it. Then click on Omnislash V.5 so the little E shows up on the left that says it is equipped. Then to use it simply just use slashing blow then just keep pressing square.