Xenosaga Episode I: Der Wille zur Macht[a] is a role-playing video game developed by Monolith Soft and published by Namco for the PlayStation 2; the game was released in 2002 in Japan and 2003 in North America. It is the first entry in the Xenosaga trilogy, and forms part of the wider Xeno metaseries. Gameplay features exploration of environments through a linear narrative, while battles use turn-based combat with the player characters fighting both on foot and piloting large mecha dubbed A.G.W.S.; combat in turn features a system of button combinations for attack types, and multiple leveling systems.
Set far in the future when humanity has left Earth, the plot follows Shion Uzuki, an employee of Vector Industries; and KOS-MOS, a battle android design to fight the hostile alien Gnosis. Forced to escape a Gnosis attack and head for the planet of Second Miltia, Shion and KOS-MOS are pulled into a fight between the Galaxy Federation and the hostile U-TIC Organization. With others who join them as they head to safety, they face a deeper mystery surrounding U-TIC’s goals and the plans of the immortal Albedo Piazzolla.
Development began in 2000 under the codename “Project X” following the founding of Monolith Soft. Intended as a spiritual successor to the 1998 video game Xenogears, multiple staff were carried over including director and co-writer Tetsuya Takahashi, co-writer Soraya Saga, character designer Kunihiko Tanaka, and composer Yasunori Mitsuda. The game received generally positive reviews from critics, and sold over one million copies worldwide. Its direct sequel, Xenosaga Episode II, was released in 2004 in Japan and 2005 overseas. The final Xenosaga game, Xenosaga Episode III, was released in 2006. The game received an anime adaptation which aired in 2005, and was re-imagined along with Episode II as part of Xenosaga I & II for the Nintendo DS.