Henry Agyei Gyamerah is a ragga musician from Ghana whose stage name is OD4, a rebus for Obiara Di Fo, which means everyone is guilty. The 4 signifies that his melody is on 4 notes. He is a proponent of raglife music and describes his music as a mix of dancehall and highlife.

Some of his popular songs are Wonya Da, Odo Nkoaa, Ten Thousand, Twe ma me, SLIMA girls and Darling a lot of which he has worked on with Ras Nigga, who he is rumoured to be going out with. He has worked with several other artists such as Okuraseni Samuel of TV2 Mentor fame, Kyikin,