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. These humans were the first to travel so distantly through Earth's solar system. They were reported missing five months after leaving Earth and presumed dead due to a pilot error. While it was declared that a crash occurred, there was no evidence of such a disaster, as the crew had been taken captive by the Galra Commander of the Galra Empire.
- Shiro became a famed gladiator champion, but escapes back to Earth a year after his capture with help from Ulaz.
- Matthew Holt was freed by alien rebels at some point and became a member of their militia; he is located by Pidge and joins the Voltron Coalition.
- Samuel Holt's status and whereabouts are unknown.
Kerberos is an inhospitable, spherical satellite covered in ice and has no breathable atmosphere. It is white in color and located at the end of Earth's solar system where it slowly orbits Pluto. There are no known inhabitants living on Kerberos.
- 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.