Not really a build, but Accuracy has me thinking - if it makes moves home in on a target (did it ever get stated that’s how it works? I’m going off hearsay here), how about high Accuracy on a slow magic barrage/multiblast? Persistent pressure, and could be brutal if you land a move that locks someone in place.
Also a friend had an idea: Vanishing Juggernaut, use the spirit clone move and vanish while your clone causes problems. Spirit Rain could also combine nicely with those moves that slam enemies into the ground.