General Cameron Merritt is an Alliance general who frequently appears in the Course Books. He is generally considered to be about Hunter's age and was promoted to general while still fairly young. Merritt also appears in the Alternate Timeline presented in Retrospectus where he was a rebel working with the alternate-version of Jason Bur'I.
Merritt is a close friend and confidant of Hunter, and was probably promoted to general by him (though this is never confirmed in the series). The two are in some ways closer than Hunter and Jason, despite different sides (Merritt is an Alliance general, whereas Hunter has close ties to the Foundation).
Merritt is not one of the higher-up in the Alliance Millitary, and still actively participates in operations, which is part of why he is Hunter's right-hand man.
General Merritt's first name is 'Cameron', though this is only stated in his character biography in The Concourse to Victory, and he is never identified by first name in any story.