Webzen will be bringing new content to MU Legend open beta users with the release of the faction Wars update on January 9th. The new content allows guilds to challenge one another "for the ascendancy of the server and to prove which fellow players' supremacy will rule over the server".
“The guild wars feature update marks the last important step to shape up the final OBT version of MU Legend. Thereafter, each following additional contents to the game will be part of the official release of the game. Talking about the official release of the game, if we are still keeping secret and for now the exact date, rest ensured however that we are steadily working on making happen what will be our most important date after the OBT one! Almost needless to say because our crowd of fans are expecting it to come, among the ranks of the big and numerous novelties for 2018, stands the mysterious Spellbinder class which will bring the number of playable characters to 5!
You can learn more on the MU Legend site.