Trying to learn the game and couldn't find a thread on this. My first (possibly mistaken?) impression...
AIR stance is strong against EARTH attacks and weak against FIRE attacks.
EARTH stance is strong against WATER attacks and weak against AIR attacks.
FIRE stance is strong against AIR attacks and weak against WATER (makes sense).
WATER stance is strong against FIRE attacks and weak against EARTH attacks.
So Water > Fire > Air > Earth > Water. Choose the right stance and you win.
VOID has no real strength/weakness, and lets you change stance if you miss using Void Strike.
So you should want to act last, right? Or if you must act first, assume void stance.