Vaan, Basch and Ashe are all lvl. 53, all have three quickenings and I think I'm fairly prepared for the battle, but he just won't die. I've tried nearly 15 times and every time I get closer to beating him, but have never survived past when he becomes immune to both physical attacks and magicks. He keeps popping cheap shots and Gigaflare sword and takes all of my characters out. I try and keep Hastega/Protectga/Shellga on throughout the battle, but they're all but useless when he's immune to physical attacks. Any ideas?!

Usually what I do in these situations is have Ashe heal everyone constantly no matter how much hp is lost from the characters, meanwhile I have Basch hack away with all he's got. I use Vaan for anything else that needs doing. Eventually the immunity will go away and you can either continue this strategy or hope you can make a decent mist quickening to finish the job.

Just beat him a little while back. I was level 60+ with my main party but don't worry, 53 is good enough. Just have all 3 with with all Green Magicks and atleast one with all Time Magicks. When he does Dispelga or your effects run out, have everyone cast Protectga/Shellga/Hastega. Then have your mage have Faith and cast Flare like there's no tomorrow. The important thing here is Flare with Faith and attacking with Bravery.

(Bubble belt could help too, gotten after Elite Mark Antlion from Mont Blanc.)

If you don't have enough bubble belts (My bazaar always has them on sale) Then Gambit Bubble to your Healer.

i just beat him. vaan was lvl53, basch and ashe lvl49. it's fairly simple. i had all of them equipped with deathbringers and bubble belts. also, make sure you have 3: rubber suits, white masks, ice/flame shields. now just pay attention at what spell he's about to do and switch around your armor. this is one way to help deal with damage. when he's immune to phys/mag, of course you really can't do anything other than run away and just continously heal your party and just wait it out. keeping your party full or close to full hp is key.

i don't have hastega but i at least haste my main healer/attacker. also, i didnt bother with protecga/shellga. if a big damage attack is going to come out, like gigaflare or w/e, try to cast reverse on all the characters you can. just watch out tho if you have to cast curaja because a reverse character will take a tremendous hit if you cast it accidentally.

just a note, you can buy bubble belts, rubber suits and white masks in balfonheim.

if u have the zodiac spear, use it

equip it, or any other 100+ weapon, to a good melee character for quick regen.

I had three bubble belts and one of those accessories that double potency of items. when the cheap shots start equip the belts and when someone needs a phoenix down equip the accessory and throw the phoenix down, they should have enough hp left after one shot to drink an xpotion. I had all three turn off gambits and just heal and wait

wow i was lvl 47 i used all 6 people but what i would do is massivly attack and use curaja to heal everyone and then when someone died i would change characters arise them and heal the party and just keep on doing it eventually he will fall