Bi Hei grew up in Jouto Village alongside Shin and Hyou. His first meeting with Shin involved picking a fight and being quickly defeated, starting their long association. He inherited prominent buck teeth and a small goatee from his father. His immediate family consisted of his younger brother, Bi Tou, who died in battle, and his wife, Tou Bi. Initially, Bi Hei exhibited profound cowardice and anxiety, especially during his first battle. Overwhelming fear gripped him amidst the chaos, finding the sensory assault of blood, excrement, and violence nearly unbearable. This fear often paralyzed him in critical moments, requiring rescue by comrades like Taku Kei. Despite this, he showed loyalty and protective instincts, saving his brother Bi Tou from an enemy soldier during the Battle of Dakan Plains. Conscripted into the Qin militia with his brother, Bi Hei reunited with Shin during the Keiyou Campaign, serving under squad leader Taku Kei. He frequently dismissed Shin's ambition to become a Great General as foolish, reflecting his own pragmatic, survival-oriented mindset. His early battlefield experiences involved forming close-knit defensive units with fellow soldiers, adhering strictly to Taku Kei's survival strategies emphasizing mutual protection. These tactics proved vital during intense engagements, such as building barricades from corpses to repel chariots and enduring successive enemy waves. Over time, Bi Hei rose from infantry soldier to leadership, becoming a 300-Man Commander and leading the Bi Hei Unit within the Hi Shin Army. As one of the oldest veterans, his tenure spanned the unit's evolution from a small 100-Man force. He fought in major conflicts like the Battle of Bayou, where he reassured anxious comrades about Shin's reliability before deployment. Personality-wise, Bi Hei maintained a pattern of bragging and mythomania, often embellishing stories or lying. After battles, he shared exaggerated accounts, such as claiming Kyou Kai surpassed Shin in combat. Despite habitual cowardice, he developed a reputation for kindness and simplicity among peers. His battlefield resilience grew through repeated exposure, though core traits of fearfulness and self-doubt persisted even as he adapted to military life.