Private Obo was a Sentinel who was part of the Search and Recovery team led by Lieutenant Nathan Hale and Captain Bo Richards that met Freedom First in Chicago in an attempt to find former Secretary of War Henry Walker. He helped defend the rebel base from an attack by a Chimera raiding party. Obo was killed when an Angel appeared and used a mental blast that presumably shattered his brain. After his death Obo's weapon, a L210 LAARK, was used by Hale to kill the Angel that killed him.