Kerberos is one of four natural satellites of Pluto and where a mysterious incident befell the Galaxy Garrison's Kerberos Mission crew consisting of Shiro, Samuel Holt, and Matthew Holt. They were reported missing five months after leaving Earth and presumed dead due to pilot error. While it was decided a crash occurred, there was no evidence of such a disaster, as the crew had been taken captive by the Galra Empire.
During an unknown year, the Galaxy Garrison sent Shiro, Samuel Holt, and Matthew Holt to Kerberos to collect ice samples. These humans were the first to travel so distantly through Earth's solar system. While later reported missing and presumed dead due to pilot error, they were in truth captured by the Galra Commander some time after landing on Kerberos and taken as prisoners of the Galra Empire. Shiro is the only known crew member to escape alive a year after his capture, while Matthew Holt was freed by unknown rebels at some point and remains missing. Samuel Holt's status and whereabouts are unknown.
- Kerberos is a real natural satellite of Pluto. In reality, Kerberos has a double-lobe shape, not spherical.
- According to Pidge, it takes the futuristic technology of Earth spacecrafts "months" to reach Kerberos. Samuel Holt implies the total intended mission length would be two months when he describes how the crew will be eating freeze-dried peas for that amount of time. The Blue Lion and pursuing Galra warship travel from Earth to Kerberos in a matter of moments. To contrast, New Horizons, launched in 2006, took 9.5 years to reach Pluto.
- Like many space objects, Kerberos is named after a mythological figure, in this case the Greek form of Cerberus, the three-headed dog guarding the Underworld.