- MU Legend Online KR Emphasizer Teaser Trailer MU Legend is the official follow-up to Mu Online - one of the first 3D MMORPGs in South Korea. Like its predecessor, MU Legend is developed by the Korean gaming company Webzen Games. A second female playable character is now available in the Korean version of MU Legend Online. The game now has five playable characters including the new Emphasizer that was just patched.