Asura, being injured from the battle with Shinigami, begins to put up a barrier around himself preparing for a deep sleep. Before the barrier closes, Maka, Black Star, Kid, and their weapons are the only ones able to get inside. Having devoured Arachne's soul, Asura grows tremendously in size and strength. When the fight against Asura begins, they do not appear to be injuring him, but Kid thinks they are as the barrier is weakening. They start a chain resonance with Soul playing the piano, but when Maka is about to perform Demon Hunter, Soul pushes himself too far and is devoured by the black blood. With Soul, the only one who can help them do a chain resonance, down for the count, Maka goes to bring Soul back, with Black Star and Kid protecting her. (thetvdb.com)