Jamarcus is a gay character that is mentioned in "Message Received ". Jay asks Cam and Mitchell about their friends, mistakenly referring to him as "LaDavid". Cam mentions that they have friends named Jamarcus and LaMichael.
In "The Verdict", he is mentioned in an "interview" with Mitch and Cam, but we don't see him at all. Jamarcus is said to be the ex-boyfriend of Raymond. It is also said by Cam that Jamarcus got all the friends and Raymond got all the confidence to go shopping in his P.J.'s.