Plot

Kratos is a warrior in the service of the Greek gods of Olympus. It is revealed in a series of flashbacks that Kratos was once a captain in the Spartan army. A fierce warrior, Kratos led his army through several victories, until finally meeting an invading horde of barbarians. The Spartan is overwhelmed by sheer numbers and Kratos is on the verge of being killed by the Barbarian King, when in a moment of desperation, he calls to the God of War, Ares, and pledges his life in servitude if Ares will spare him and provide the power to destroy his enemies.
Ares hears Kratos' prayer and bonds the "Blades of Chaos" (a pair of blades attached to chains and forged in the depths of Tartarus) to his new servant. Kratos then returns to the confrontation with the Barbarian King and decapitates his foe. A victorious Kratos then wages war against all Greece, and eventually leads an attacks on a village occupied by worshippers of Athena. Ares tricks Kratos by placing his wife and child in the village, who Kratos accidentally kills. Although Ares intends for this act to make Kratos the perfect warrior, Kratos renounces his servitude to Ares. The oracle of the now destroyed village curses Kratos, and the ashes of his family adhere to his skin, turning it ash-white. Now the "Ghost of Sparta", Kratos is plagued by nightmares of his horrible deed and commits to ten years of servitude to the other gods of Olympus. Eventually tired of his servitude, Kratos summons Athena, who states that if Kratos performs one final deed—the murder of Ares—he will be forgiven for the murder of his family. Athena assigns Kratos to destroy Ares because Zeus has forbidden the gods to fight each other.
Kratos is guided by the goddess Athena to the city of Athens, which is under siege by Ares' minions. Kratos battles his way to Athens' oracle, but not before also having a strange encounter with a grave digger, who encourages Kratos to continue with his task. Finding the oracle, Kratos learns the only way to defeat Ares is to locate and use Pandora's Box, a legendary artifact which can give a mortal the power to kill a god.
After traversing the Desert of Lost Souls, Kratos summons the Titan Cronos. Cronos has the Temple of Pandora chained to his back: a punishment inflicted by Zeus for Cronos' role in the Great War. Kratos climbs the Temple for three days before reaching the entrance, and on entering overcomes an array of deadly traps and an army of monsters. Kratos eventually finds Pandora's Box, but on leaving the Temple with the artifact is murdered by Ares, who is aware that his former servant has succeeded. As a group of harpies take the Box to Ares, Kratos falls into the Underworld. Kratos, however, battles his way through the underworld, and with the aid of the mysterious grave digger, who mentions that Athena is not the only god watching over him, escapes and returns to Athens.
Recovering Pandora's Box from Ares, Kratos opens it and uses the power to become god-like. Despite Ares' best efforts to destroy Kratos both physically and mentally, including being stripped of the Blades of Chaos, Kratos survives and kills his foe with the ancient Blade of the Gods. Athens is saved, and although Athena states that Kratos' sins are forgiven, the gods will not rid him of his nightmares. Kratos then attempts to commit suicide by casting himself into the Aegean Sea, but Athena intervenes and brings him to Mount Olympus. As a reward for his services to the gods, Athena grants him Athena's Blades and Kratos Becomes The New "God Of War."