Gai Mou, alternately known as Kai Meng or the Raging Bull, holds the rank of Great General within the Wei military and stands among the founding generation of the Seven Fire Dragons. His past is marked by involvement in the Fire Dragons' internal strife, siding with Earl Shi and Rei Ou against Tai Ro Ji, Shou Sen, and Ba Tou. This conflict culminated in Tai Ro Ji's demise and Gai Mou's subsequent 14-year imprisonment in an underground prison as retribution. Following his release, he returned to active duty under Go Hou Mei during Wei's ensuing wars.
Physically imposing, Gai Mou possesses a frame larger than contemporaries like Mou Bu or Mou Gou. In battle, he dons bright red armor. His features include long black hair secured in a ponytail, a long beard, a fu manchu mustache, and thick eyebrows. Distinctive cross-shaped silver scars mark his face, contributing to an overall sinister aura.
Gai Mou exhibits an easygoing and boastful personality, frequently exaggerating his own capabilities. He displays a simple thought process, often misinterpreting tactical instructions and acting on impulse—such as loudly issuing challenges that breach operational secrecy. Openly lecherous, he regularly indulges with multiple women, citing his lengthy imprisonment as justification. Philosophically, he rejects idealistic views of warfare held by figures like Ren Pa or Ou Ki, dismissing concepts of dreams or deeper significance in battle. He reduces war solely to a brutal exercise where the strong slaughter the weak, a perspective that led Ou Ki and Ren Pa to deem him unworthy of dueling due to his lack of substantive reason to fight.
His documented engagements include several key campaigns. During the Wei invasion led by Qin's Tou, he commanded reserve units, initiated a duel with Shin after challenging the Hi Shin Unit leader, and overpowered him until a strategic retreat was ordered. His forces later captured the Hi Shin Unit's strategist, Ka Ryo Ten, resulting in a hostage exchange negotiated with Shin. He remained in Wei to secure its borders during the War of the Three States while Go Hou Mei assisted Qin. In the Conquest of Han, he led over 60,000 soldiers against the Gyoku Hou Army, spearheading frontal assaults while Go Hou Mei's reserves executed flanking maneuvers.
Gai Mou's combat prowess is formidable, statistically rated at 97 in strength. Prior to imprisonment, he claimed over 100 enemy generals' heads. He wields a large podao with masterful proficiency, capable of cleaving through multiple soldiers in a single stroke and delivering blows comparable to Ren Pa's force. His physical power allowed him to overpower warriors like So Sui and send Shin flying during their initial duel. Despite tactical limitations stemming from his dense nature, he effectively commands troops from the front lines, relying on his strategist Jun Sou for planning. His leadership and intelligence are rated 85 and 80 respectively, complemented by extensive "S"-ranked battlefield experience.
His character development remains consistent across appearances, maintaining core traits and philosophy while continuing to serve as a prominent military asset for Wei in major conflicts.