Hey! I have a great idea. Inner Classes. Inner classes can only be unlocked after mastering your school. Inner classes have special powers. Here is a list of some inner classes.
Balance: inner class- Peace The peace class can stop the enemy from using hostile spells for a certain amount of turns. They can use passive spells.
Astral: inner class- Universal Universal is an upgrade from astral. It allows the user to attack with astral, other than use passive spells that improve. It would hurt extreme.
Fire: inner class- Ash Ash would use a spell that would burn the enemies, until death. Depending on the ash card, it would kill them in a certain amount of turns.
Life - Can't Touch This You can't be the target of spells or cheats for 4-6 turns. Only usable in multiplayer battles (not when you're 1v1 or soloing in PVE).
Balance - Off Kilter Filter All spells in your deck, spell effects currently in action (auras, DoT auras, wards etc) and sources of damage count as Myth spells/effects for the next 4-6 rounds. (This is as close as I could come to a balance prism as I knew how)
Death - Doppelganger (Polymorph Your Opponent) You become an exact copy of your opponent, including health/resist/crit/critblocking/pip chance, deck, etc. for 4-6 rounds. Can be used against any entity in the game; cheats not included, sorry Luska wannabes.