Remains in play. The Sorcerer is surrounded by a shield of fire that blocks enemy attacks. The Sorcerer, his mount and all models in any unit he joins have a 5+ Ward save. This replaces their Daemonic aura. Once it is cast, Yellow Fire remains in play until the Sorcerer chooses to end it (which he can do at any time), it is dispelled, he attempts to cast another spell, or he is slain.