Netmarble’s mobile massively multiplayer online role-playing game Lineage 2: Revolution launched in the West for the first time last month. It’s ranked No. 6 in the role-playing category on both the U.S. Google Play Store and the Apple App Store, according to market researcher App Annie. And the South Korean gamemaker is hoping to get more players on the battlefield with two new modes it’s adding on December 13.

Lineage 2 is debuting weekly live events called Fortress Siege and Open Siege. Fortress mode features 50-vs.-50 combat between two clans, and the objective is to seize the opponent’s castle by imprinting on their Holy Artifact. In order to participate, each clan will have to enter a process to claim a fortress. Clans will bid on fortresses from midnight to 7 p.m. Pacific every Thursday, and the Fortress Siege will take place from 8:30 p.m. to 9 p.m. Pacific on Friday. All participating players will receive rewards such as in-game currency, experience points, and buffs.

Open Siege is aimed at players who are above level 11. The mechanics are similar to Fortress Siege, except it’s 30-vs.-30 combat instead. Players can join Open Siege with a maximum party of five, and they’ll be sorted by combat power and level. Normally, it’ll take place starting at 8:30 p.m. and ending at 9 p.m. Pacific every Tuesday, Thursday, and Saturday starting on December 19. Players will be able to play Open Siege on a modified schedule this week on Wednesday, December 13, and Saturday, December 16. Players’ rewards will depend on their contributions to the match.

Netmarble is powering up three new servers in North America and Europe in anticipation of the new modes. It’s also rolling out some gameplay improvements and a new in-game shop.

Lineage 2: Revolution launched a year ago and is a huge hit in Asia, hitting No. 1 on the charts in several different countries. Based on the NCsoft’s PC title Lineage II, it brings Diablo-esque raids and massive battles to mobile screens. It’s been gearing up for its Western debut for a while, and even teamed up with late-night TV host Conan O’Brien to prime audiences for its release and to tease Fortress Siege at TwitchCon. Next year, it plans on adding even larger battles with its 200-player Castle Siege mode.