Card sounds may differ from in-game as they get updated.
Endurance - Units with Endurance ready at the start of each players turn, so they can attack and still be ready to block during the enemy turn. Additionally, they are completely immune to enemy stun and exhaust effects.
Unleash - When you play this card, create and draw a copy of it. Discard it at the end of the turn. Cards with Unleash can’t cost less than 1.