The Mjolnir Project is a Myth II plugin that sets out to take the units from an old series of Bungie games called Marathon and port them into the Myth II engine. This plugin focuses on recreating the monsters as close as possible to the originals.

Marathon was a landmark first-person shooter, first released for the Macintosh in 1994, which introduced many new features and concepts to the genre including vertical aiming and mouselook; dual-weilded and dual-function weapons; versatile multiplayer modes such as King of the Hill, Kill the Man with the Ball, and cooperative play; friendly NPCs; and a deep and intricate narrative. The sequel, Marathon 2: Durandal, was released in 1995, improving on the engine technologies and greatly expanding the scope of the series. In 1996, Marathon 2 was ported to Windows 95, and the Marathon Infinity package was released, including a new scenario using a modified Marathon 2 engine, and most importantly, the tools used to build it, Forge and Anvil. In the year 2000, Bungie released the source code to the Marathon 2 engine, and the Marathon Open Source project began, resulting in the new Marathon engine called Aleph One. Finally, in 2005, Bungie authorized free redistribution of the entire Marathon trilogy and all related files. This means that the entire trilogy can now be legally obtained for free and played on nearly any computer.

To download the Marathon trilogy game files, the Aleph One engine and source code, and numerous graphical enhancements created to bring a modern polish to these classic games, please visit Marathon Open Source.