After analyzing the narrative threads woven throughout the God of War series, I have developed a theory regarding the origin of Kratos’s iconic facial scar. This theory centers on his relationship with his brother, a topic frequently debated within the community. If you prefer to avoid speculation regarding Kratos's family history, please consider this your spoiler warning for God of War III and related lore.
The line, "Spartans never fall on their back, right brother?" has been a subject of intense scrutiny in fan forums. Based on my assessment of the character dynamics established in the series, I propose that this dialogue originates from their shared youth during their rigorous Spartan training.
My theory suggests that God of War: Ghost of Sparta (GOW:Gos) could feature a flashback sequence detailing their formative years. During this time, Kratos naturally excelled, pushing himself far beyond the capabilities of his peers. When his brother struggled to keep pace, Kratos, driven by the harsh Spartan ethos, would frequently admonish him with the phrase: "Spartans never fall on their back!!"
As the disparity in their combat prowess grew, so did the brother’s resentment. He felt inadequate and perceived Kratos’s discipline as a form of rejection. I believe this emotional friction reached a breaking point where the brother, fueled by jealousy and a desire to humble Kratos, struck him while he was vulnerable—perhaps while he was sleeping—inflicting the signature scar across his face.
In this scenario, as Kratos lay incapacitated on his back, clutching his wound, his brother would have weaponized Kratos’s own mantra against him: "Spartans never fall on their back, right brother?" This act of betrayal would serve as the catalyst for Kratos’s emotional detachment, explaining why he would later leave his brother to face his fate in the underworld.
This interpretation aligns with the tragic, cyclical nature of the Kratos narrative. I welcome your perspective: based on your understanding of the God of War timeline, how do you believe Kratos received that scar?