Yor'sahj attacks the Raiding ally with the lowest remaining health if able.
Call Blood of Shu'ma (Deathwing Stages 2+): When Yor'sahj deals fatal combat damage to a defending Raiding ally, that ally's controller reveals the top card of his deck. If it's an ability, Yor'sahj deals 3 shadow damage to that Raider's hero. If it's an ally, flip a Deathwing card. If it's an equipment, each other Raider discards a card.