i need help i keep getting his life down to the final thing but then i die what should i do?

Keep doing the reaction commands and that will destroy all of the water clones in a short time.

I've found it that it works very well if you use your Drive modes ONLY when you need healing (Since they automatically restore health to full), deal as much damage as you can while you're driving (I perfer Wisdom mode for this, since it keeps me out of range of his EVIL attacks), and concentrate more on staying alive than actually attacking him otherwise.

Of course, it's still an unbelievably hard fight no matter what you do XD

wait to use drive until he starts using different attacks than he begins with, they deal more damage, as for the water clones, i have no advice except............... kill them faster...? LOL