rAthena is a collaborative software development project revolving around the creation of a robust massively multiplayer online role playing game (MMORPG) server package.

Written in C++, the program is very versatile and provides NPCs, warps and modifications. The project is jointly managed by a group of volunteers located around the world as well as a tremendous community providing QA and support. rAthena is a continuation of the eAthena project.