Perk is a special and a magic abilitiy, helping you to take down your opponent in a fight. You can activate perks in the battle after collecting a certain amount of energy.
Energy is collected by performing quick time events (taps and swipes). Once you've filled up enough energy bars, you will see available Perks' icons on the left side of the screen. Tap the icon to perform a Perk during your next turn.
You get to choose a new Perk once in a few level-ups.
To choose or re-assign your active Perks go to the [Perks] section in the Menu on the left.