Instructions
Switch to the skill card that is in your deck during a battle by pressing the "S" key or "Z" and "X" keys at the same time.
Cast the skill card that you chose by pressing the "D" key or "X" and "C" keys at the same time.
The skill card can be cast during a change in the game on its own. This will make the attack happen without having to press a button. This will only happen in Soku.