Most things I've tried! Attack, defense, wards, illusion, breaking other people's wards and illusions, paralysis, ah, I can do this really cool move where I turn stuff into dragons.

[ Koumyou counts them off on the fingers under the ball of lightning, starting over as needed. ]

One time when I was in training, I built a big buff snowman to shield everyone from an avalanche! Though I had to use everyone else as a battery to do that. One body only produces so much chi at any given moment.