While dealing with Kosmos, who had altered itself into a sort of intergalactic prison, Thanos released Skreet and Starlord. He found another empty chamber. It was explained that the other prisoner had been the first herald of Galactus... now only known as the Fallen One. Now that he was free he was set on confronting his former master.
Skreet and Thanos decided to intervene. After a battle, the Fallen One was defeated by the ignition of bombs placed within nearby gas giants. Galactus had no interest in reclaiming the Fallen One and left his to Thanos's discretion. Thanos claimed he would make the Fallen One his own herald.