The year she turned eight, Sofi lost her parents to the chaos of war. The Bucks Team sniper Argus found her alone in the smoky rubble and brought her under his care. Growing up, Sofi was a strong spirit who refused to be defined by her childhood trauma. She rejected all offers of help and insisted on solving problems on her own. By the time she turned fifteen, Sofi had mastered every battle technique imaginable, even honing her reconnaissance and sniping skills to match that of her adoptive father. She argued frequently with Argus, who strongly opposed her joining the Bucks Team, even though she could strike a tie in combat with any Bucks Team member. The day she came of age, a starry-eyed Sofi ran away to join the Agurts 303rd Marines, swiftly passing the test to become the division’s youngest female SA pilot.

八歲時在戰亂中失去父母，被公鹿小隊狙擊手阿爾戈斯救回並收養。雖然年幼遭遇不幸，但蘇霏從不願接受過度的照顧，再艱難的事也會倔強地不斷嘗試，若有人想要暗中幫忙反而會遭到她的訓斥。 十五歲就將各式遠攻近戰武器練得樣樣精通，偵察與狙擊技術更是深諳養父精髓，與公鹿特戰兵相比也能戰個旗鼓相當。但養父堅決反對她成為公鹿小隊正式成員，她唯有在成年那天偷偷離開，加入了第303海軍陸戰隊，並在短短數月間通過考核，成為了隊中最年輕的強壘女駕駛員