Rohan: Blood Feud has many of the features one might expect from an MMO, such as questing, missions, a pet system, mounts, and a level grind. The rest of the game is highly PvP centric and all about consequences. There is even a feature that keeps track of the last 50 players who killed you on a personalized hit list. Where some games have the ability to teleport to your in-game spouse, Rohan takes the "blood feud" of its title quite seriously, allowing players to teleport to the whereabouts of characters on that hit list. While the game sees updates for various content, it's the PvP fans for whom this title holds the most.
US Official Site: http://www.playrohan.com