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.
Warcry - Each time a unit or Relic Weapon with Warcry attacks, it grants a permanent bonus to the top-most unit or weapon in your deck. Even if it's a few cards down, you'll get to stack up the bonuses on it over multiple turns.