Hailing from Qin's nobility, So Sui entered military service young and rose through the ranks via tactical skill and martial prowess. He became Commander Kaku Bi's trusted lieutenant and right-hand man in the Kaku Bi Unit, fighting in campaigns like the invasion of Wei's Sanyou. During the siege of Kinrikan, he breached defenses while the Hi Shin and Gyoku Hou Units distracted the enemy. Following Kaku Bi's assassination by Wei General Rin Ko, So Sui led 700 survivors to join the Hi Shin Unit, pledging loyalty to Commander Shin while vowing to honor Kaku Bi's legacy in battle. So Sui bears a distinctive scar across his left eye and cheek, sports long black hair, a mustache, and a goatee. He wears standard Qin commander attire accented by a brightly colored cape signifying his rank. His personality blends disciplined seriousness with profound loyalty and sentimentality. He demonstrates unwavering commitment to commanders he judges capable, first serving Kaku Bi and later transferring his allegiance to Shin, while maintaining strong emotional ties to his former commander's memory and motivations. Within the Hi Shin Unit, So Sui serves as third lieutenant, commanding his own sub-unit. Initially leading 1,000 soldiers, his forces grew to 5,000 troops (3,000 cavalry, 2,000 infantry) designated the Black Hi Hyou Unit after Qin's military reforms. His responsibilities include tactical planning, frontline command, and logistics organization, which he managed before strategist Ka Ryo Ten's arrival. His combat prowess centers on glaive mastery, proven when he decapitated Wei commander Gi Ryou at Sanyou. He also clashed with formidable foes like Wei's Gai Mou, nearly blocking a lethal strike despite being overpowered. Stat assessments track his growth: leadership (83→85), intelligence (85), assistance (88→90), and strength (80→81). Key campaign actions include: - **Sanyou Campaign**: Objecting yet joining Shin's charge at Gen Pou's headquarters, ordering the Retsu Brothers to protect Shin. He later held off Wei troops during Shin's duel with Rin Ko and killed Gi Ryou when he tried to interfere. - **Coalition Invasion**: Leading 150 cavalry under Ka Ryo Ten's orders to cut off Zhao General Man Goku's retreat, enabling Shin to slay him. - **Fire Dragons of Wei Arc**: Suffering injuries from Gai Mou early in the Choyou Campaign, sidelining him for its duration. - **Koku You Campaign**: Being incapacitated by Zhao Commander Ba Tei on the third day of fighting. - **Three Pillars Arc**: Promotion to 5,000-man commander as part of military reforms after Qin's defeats. Within the Hi Shin Unit, relationships reflect mutual respect. Shin values his tactical insights, while Kyou Kai acknowledges his strategic strength, stating the unit "has need of that man in the future".