Henry Agyei Gyamerah is a ragga musician from Ghana whose stage name is OD4. OD4 is derived from 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 strong ties with the TV3 Mentor show and is believed to have contributed lyrics to "Yeresei adze", the Western Region representatives' song.