Might & Magic Heroes Online. The trailer shows off the gameplay elements which includes brand new features suited to a persistent browser game.
According to the publisher, "Right from the start, players will be able to choose their hero from two of the most famous factions: Haven and Necropolis. They will then venture out into the realms of Ashan, where they will control their powerful hero and his armies as they travel from the glorious temples of Elrath to the undead lands of Nar-Heresh."
Gamers can also apply to beta test the game at the official site.