Lineage II is a massively multiplayer online role-playing game (MMORPG) for Microsoft Windows and the second game in the Lineage series. It is a prequel to Lineage and is set 150 years before the first game. It has become popular since its October 1, 2003 launch in South Korea, reporting 1,000,918 unique users during the month of March 2007. To date, the game has been played by more than 14 million users, most of whom are based in Asia.

A game engine is a software framework primarily designed for the development of video games and generally includes relevant libraries and support programs such as a level editor. The "engine" terminology is akin to the term "software engine" used more widely in the software industry.