Maken X is a first-person hack and slash video game developed by Atlus for the Dreamcast. It was published by Atlus in Japan in 1999, while Sega localized and released the game overseas in 2000. Gameplay has the Maken—a sentient sword-like being—"brainjacking" or taking control of multiple characters across a variety of levels; combat is primarily based around short-ranged melee attacks, with some characters sporting additional abilities such as ranged attacks.

The story is set on near-future Earth during a time when the world is descending into chaos due to natural disasters and rising political tension between China and the United States. When the facility where the Maken was developed is attacked, the sword bonds to main heroine Kay Sagami and is sent on missions against the group responsible for the attack. Depending on dialogue choices and brainjacked characters, seven possible endings can be achieved.

Concept work began during the middle of production on the Persona 2 duology. Featuring staff from the Megami Tensei franchise including artist Kazuma Kaneko and composer Shoji Meguro, development took approximately two years. It was the first game developed by Atlus to feature full voice acting, and one of the company's earliest fully 3D titles. The game was met with mixed reviews, but sold well in Japan. An enhanced remake for the PlayStation 2, Maken Shao: Demon Sword (魔剣 爻, Maken Shao), was published by Atlus in Japan in 2001 and in Europe by Midas Interactive Entertainment in 2003. It changed a number of gameplay elements, introduced further cutscenes, adjusted the music, and added the third-person perspective in response to a common trend in Japan of first-person games causing motion sickness.