River Baldwin was one of the many people that was in the Carrier when it took of to space, when it was summoned back to her home station. He is also a Century Baby with powers similar to those of the Drummer, allowing him to control and warp information. Orphaned becauswe the events of the Number of the Beast, River was took under the protection of the High, who considered him his adopted son.

River was pivotal to help the Authority and the Carrier to navigate and fought the dangers they found in the perpetual darness of the external void, and key element in the fight for return and the attack of Mondregon.