Mastery 4: +1/+1.
Card sounds may differ from in-game as they get updated.
Ambush - An ambush unit can be played at the end of the enemy player's turn, or any time they are attacking you. If you played against a Killer or Relic Weapon attack, an Ambush unit will jump in the way to block that attack.
Mastery - All damage dealt by units with Mastery count towards its Mastery ability. When its Mastery number is met, it uses its Mastery ability.