Kratos Aurion, born into Tethe’alla’s nobility, honed his skills as a knight under Princess Soleil’s service. His path intertwined with half-elf siblings Mithos and Martel Yggdrasil when aiding their efforts to warn the Tethe’allan king of Sylvarant’s impending invasion. The king’s dismissal led to the capital’s destruction and Kratos’ exile, binding him to the siblings and Yuan as the Four Kharlan Heroes. Together, they wielded Origin’s Eternal Sword to end the Kharlan War, splitting the world into twin realms: Sylvarant and Tethe’alla. Martel’s assassination fractured the group. Mithos, warping her vision of equality, established Cruxis to purge the world of life’s imperfections. Kratos ascended as a Seraphim, enforcing the Chosen system to harvest souls for Martel’s revival. Centuries later, he defied Cruxis to save Anna—a human test subject—marrying her and fathering Lloyd. Pursued by Cruxis agents, Anna’s Exsphere removal triggered a monstrous transformation, compelling Kratos to end her life. Presuming Lloyd dead, he resumed his role as Sylvarant’s overseer. Disguised as a mercenary, Kratos guarded the Chosen Colette Brunel while covertly mentoring Lloyd. He trained his son in swordsmanship, subtly steering him toward exposing Cruxis’ tyranny. His apparent betrayal at the Tower of Salvation masked deeper loyalties; he leaked intelligence to rebels and sabotaged Mithos’ schemes. Confronting Lloyd in Torrent Forest, Kratos tested his resolve to reunite the fractured worlds. Defeated, he sacrificed his mana to shatter Origin’s seal, enabling Lloyd’s victory. Immortality, granted by a Cruxis Crystal and ingested Aionis stone, amplified his swordsmanship and spellcraft—evident in techniques like Judgment and Lightning Blade. Stoic yet haunted by Anna’s death and Lloyd’s abandonment, his icy demeanor thawed during their final clash, revealing regret and reluctant hope. Post-war, he retreated to Derris-Kharlan to dismantle Exspheres, bidding Yuan farewell as the comet drifted beyond reach. Though his ultimate fate faded into myth, his legacy endured through Lloyd’s ideals—a testament to Anna’s dream of unity.