How in the world do you beat black element?

Seeing as this fiend is the final boss in the cloister place, it is there fore the hardest so you need to be at a much much higher level, I am talking level 90+, SERIOUSLY.

Ok
The black elemental has 9999hp and is NOT the last boss in the cloister.
In fact it is only the second out of 7
So just try to get you're hits above 9999

I used Reflect,Shell and Protect..when he uses Flare it will reflect back to him.

OK, all those other tactics aren't as great as mine (no offence).

All you do is use 3 gunners "Table-Turner" ability. This ability does damage to the fiend REGARDLESS of it's defence. If you're on about lv55 or higher, you should beat it before he can use ultima. I killed him in 1 shot 'coz my characters were 90+!

My Lv. 56 Paine killed him in one shot by using the Dark Knight's "Charon". If you're on a level lower than 50, it's going to be hard once you get about halfway. I suggest leveling up first.

[color=blue] have alchimist mix a gem and holy water it does about 12,000 hp.

I have the HDed international version on the PS Vita. I've attempted fighting black element twice, but every time the fight starts, he casts ultima immediately and kills everyone. I literally have no time to do ANYTHING. I've looked up many, oh so many great strategies for taking down this boss easily, but I can't do anything if he kills me instantly, is there any way to guard against ultima? Do I just need to get one of my characters health above 9999? If it helps, I have: key to success x1. The garment grid that has the double HP effect, and I think the best other accessory that boosts HP is an iron bangle which is only 20%. I also have all the dress spheres except for: lady luck, trainer, mascot, and whatever that psychic type was that comes with the international ver.