A military prisoner shipped to Earth by Agrippa Maintainer.

Spoiler

Nander was an elite soldier during the Dark History. The Moonrace's cryogenic freezing techniques have allowed him to survive for thousands of years after the end of the war, at the cost of sustaining severe brain damage. He is delusional and almost childlike when not on the battlefield. Though no definite answer is given, a scene in the series, in which the face of the XXXG-00W0 Wing Gundam Zero appears in his memory, suggests that Corin came from the After Colony era.

(Source: Gundam Wiki)