The setting of Xenoblade Chronicles originates in a world that was nothing but endless ocean until two titanic gods, the Bionis and the Mechonis, came into existence and battled each other until only their frozen corpses remained. In the eons following their battle, they became the home of multiple forms of life. The Bionis is home to organic lifeforms, most prominently the humanoid Homs, who are virtually identical to humans both in appearance and biology; the diminutive and furry Nopon, and the avian humanoid High Entia, whose lifespans span centuries. Conversely, the Mechonis is home to the mechanical humanoid Machina, whose lifespans span several millennia.A key weapon used by the Homs in the battle against Mechonis is the Monado, a mystical sword which grants visions of the future to its wielder when fully controlled.
The game's main character is Shulk, a young Homs scientist who lives in Colony 9 on Bionis. During an attack by Machina warriors called Mechon, Shulk comes into possession of the Monado. During his journey, Shulk is joined by Reyn, one of Shulk's childhood friends and headstrong member of the Defence Force; Dunban, a former wielder of the Monado and the brother of Shulk's childhood friend Fiora, who also joins Shulk; Sharla, a medic and sniper from Colony 6; Melia Antiqua, princess of the High Entia and a High Entia-Hom hybrid; and Riki, a Nopon chosen as the hero of his village.
