Kratos is displayed as a cold and heartless mercenary in the game, though is also an expert in swordsmanship, a fact that makes Lloyd angry. The only thing he has in mind at the beginning of the game is to protect Colette, as that is what he is assigned to do. However, as the journey processes, Kratos begins to open up a little, giving out hints about a past where he did a terrible mistake.
Throughout the early stages of the game, Kratos displays outstanding knowledge of the ancient world, raising Raine’s suspicions as to his true intentions. Despite his malevolent secret agenda, Kratos takes a keen interest in Lloyd’s development as a warrior, although he takes a fairly callous approach to this. Through a side-quest, Kratos will train him in swordsmanship and give him advices that help the younger boy to grow.
Despite his long life and many years of experience, Kratos is, up until the end of the game, a fatalist, for a long time not realizing that Mithos’ way is not the only possible way to save the worlds. It is Lloyd’s actions that make him realize how much choice and control of his destiny he really has.
Four Seraphim, Cruxis
Kratos’s story actually begins approximately 4000 years before the events of “Tales of Symphonia” take place. Kratos, the only human companion of the hero Mithos Yggdrasill, traveled the world and helped to put an end to the Kharlan War, a war spanning one thousand years.
During these adventures, Mithos formed pacts with each of the Summon Spirits in the world. After the pact with the King of Summon Spirits, Origin, was formed, a seal based on Kratos himself was created to prevent anyone else from gaining Origin’s power. This seal further prevented anyone from contacting Origin unless all of the mana was released from Kratos’ body. Essentially, the seal could only be broken once Kratos’ mana was released, ending his life. Mithos then had Origin create the Eternal Sword, which he used to split the world in two, thereby creating Sylvarant and Tethe’alla.
Shortly after Mithos, Kratos, Yuan and Martel ended the war, they were betrayed by a human who had aided them during their journey. This enigmatic human killed Martel. Mithos, driven mad with grief, misinterpreted her dying wish of a world free of discrimination believing it to be a wish for everyone to be the same. Mithos then established the order of Cruxis, with he, Kratos, and Yuan as its first angels. Since Kratos was human, and had no elven blood in his veins (unlike Mithos and Yuan, who were half-elves), he was forced to ingest a magical rock called Aionis, which allowed him to cast magic and use magical weapons, in order to become an angel. The companions became three of the Four Seraphim, with Martel being the fourth, ascended to Derris-Kharlan and founded the Church of Martel. They also founded the Desian Organization, designed to aid Mithos in his plans.
After learning about Mithos’s plans for the “Age of Lifeless Beings,” descending upon Sylvarant. There he met a human woman named Anna, a research subject in the Angelus Project which attempted to culture a Cruxis Crystal within a human host, similarly to the way an Exsphere is made. The two fell in love.
Kratos soon realized that there had to be a better way to reunite the two worlds, and so he began to search for a way for a human to wield the Eternal Sword, the omnipotent weapon that Mithos had used to split the worlds. However, the pair was forever pursued by Cruxis, and soon they had a child, Lloyd. Eventually, the Desian Grand Cardinal Kvar caught them, at which point Anna’s Exsphere was removed. This caused her to become a mindless monster. She attacked the infant Lloyd, who was only saved after their pet Noishe interfered. These events temporarily caused Anna to regain her old self, at which she begged Kratos to kill her. He could not bring himself to do it, however, and Anna soon lost control again. She once again turned on Lloyd, and with Noishe too injured to help, Kratos killed her in desperation to save his son. Kvar then attacked, causing Lloyd, Noishe, and Anna to tumble down a cliff near the Iselia Human Ranch.
Kratos managed to defeat Kvar and his men, and then descended the cliff, only to find Desian corpses that were half devoured by monsters. Believing family to be dead, Kratos lost all meaning in his life. He soon returned to Cruxis, where he aided Mithos, believing that the half-elf would reunite the two worlds after Martel was revived. It is not known why Kratos didn’t kill Kvar for his actions immediately afterwards.