ok, so from what I've saw, her raging damage doesn't deal as much damage as I thought.. under 2k for all allies it seems? but that's with her atk lowered, which should be easy..mordred+jorm/triton
use your water team for sure.. use mordred, as she can use her max overdrive meter thing and debuff defense without an extra skill, gabriel have the 2nd def debuff, use chaos magic as extra skill but not til she's raging ofc, cause it will clear yatagas' def buff to herself after her strong atk or if she increases her def with normal atk in rage mode...it's a strong buff so your damage will lower a lot.. that only if she use it twice though.
remember gabriel increase burst gauge for allies with each hit, unlike any dark kami, nike healing will make sure they all survive til she's stunned, so you can use oceanus for a strong burst
though i'm sure without nike you could survive anyway.. as it is for now, try to get more of the ATK weapon like you did with the gun, not that it matters too much... you can win with both dark and water for sure without using elixers
but try with water, i don't think it'll be hard at all... i will try ragnarok this time, hopefully we can both win
why not try both and record both? XD