Kerberos is one of five 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 - the first humans 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, Matthew Holt and his father were on Kerberos, drilling into the icy surface, when the Galra appeared and captured them. Because of a lack of evidence surrounding their disappearance, Galaxy Garrison pronounced them dead. 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 was taken to a work camp with prisoners deemed too weak to fight, and was later placed in a prison under Lotor's control with other imprisoned scientists. He is rescued during a failed trade with Zarkon and returns to Earth.
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.
- The Galaxy Garrison mission was originally intended to feature Charon, but due to disagreements on the moon's pronunication, the script was changed to feature Kerberos.
- 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.