Card sounds may differ from in-game as they get updated.
Empower - Does something when you play a power card.
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.
Pledge - On your first turn, a card with Pledge can be played as a Sigil.