lol, definetly wisdom. See, you have to memorize his attack form. You can tell by his different form of stance what he's gonna do next. Like a crouch confirms the water attack. Personally, just jump to wisdom and forget ur motion, just keep pressing that button and ur swell. If you have no magic, jumping and keeping Allys alive can sometimes fail, but is usually a 90% way of good technique.
Have fun, and "DANCE WATER DANCE!"