Evergreen MU Online is still going really strong under developer Webzen in South Korea. The game recently welcomed the Season 11 update, part of its 14th anniversary celebrations. Players are introduced to a brand new continent, storyline (revival of an ancient kingdom), new weapons, and monsters.
and a new class known as Dark Elf. The global English server is just a few updates behind.
Correction: Please note that the Dark Elf is not a new playable class, but a new boss monster.