|“||The Raging Bull.||”|
—Ryuu Koku referring to Gai Mou.
Gai Mou is a very huge man that wears armor. He has long black hair and a long beard.
Gai Mou is an easy going laid-back General who only goes on the battlefield if he finds someone interesting to duel. He is very boastful to the point of even saying lies about his strength.
He also appears to be rather dense often having his lieutenant Jun Sou chiding him on his incompetence. An example of this is shown when he misinterprets Jun Sou's explanation about Shin going as far to assume Shin killed Ou Ki and Kyou. Another example of his simple-minded attitude is when he yelled his name and rank at the Hi Shin Unit in hopes of having a one on one duel with Shin at the risk of giving away his location to everyone (which was ultimately successful).
Gai Mou is also rather lecherous as seen when he is indulging himself with five women (claiming to be making up for 14 years of being imprisoned) before clashing with the Hi Shin Unit. He is later seen with them again when he questions Ka Ryo Ten after having some action with his concubines.
Philosophically, he sees Ren Pa and Ou Ki's opinion of war as a struggle of dreams and sentiments as a delusion meant to disguise the slaughter for what it really is. Thus he concludes that war is just a practice where the strong slaughter the weak. With this, Ou Ki and Ren Pa never took his challenges to duel him seriously and would withdraw as he didn't have a reason to fight that was worthy enough for them to consider.
At some point, Gai Mou along with Rei Ou sided with Earl Shi's conflict against Tai Ro Ji, Shou Sen and Ba Tou, three other Fire Generals with Tai Roji being personally responsible for the death of Earl Shi's younger sister. This resulted in the deaths of the opposing Fire Dragons.
As a punishment, Gai Mou was incarcerated in an underground prison for 14 years along with his fellow Fire Dragons.
After Tou leading a Qin army invasion in Wei, Great General Go Hou Mei requested the assistance of the three surviving Fire Dragons. As the fight started, Gai Mou was appointed in charge of the reserve units. While he was in his tent having some 'fun' with ladies, Jun Sou informed him of the Hi Shin Unit's threat and asked for back up. Gaimou retrieved his glaive and went outside, starting to fight the Qin soldiers. He called out for Shin with his loud voice and challenged him to come and face him one on one. Despite Jun Sou's doubts, Shin actually answered the call and the two engaged in a duel, with Gai Mou clearly overwhelming his opponent. At that point, however, a soldier informed the great general that it was time for him to retreat, as Jun Sou had a special gift for him. Gai Mou went back to his tent where soldiers brought him a gift - the Hi Shin Unit strategist Ka Ryo Ten. However Jun Sou was captured too, and they had to negotiate. Gai Mou asked Ten what her desire is, and why she is on the battlefield. Depending on her answer, he promised he would kill her, or let her go. Ten told him that her desire is to win as many battles as she can with the Hi Shin Unit and help Shin achieve his dream. Surprisingly, Gai Mou was satisfied with her answer. With the whole battlefield watching, Shin brought Jun Sou, and Gaimou brought Ten. The hostage transfer was done without a fight and Ten returned to the Hi Shin Unit, while Jun Sou returned to the Gai Mou Army.
While he didn't appeared, it's possible that Gai Mou and his armies stay behind to safe guard and secure the borders of Wei while the Go Hou Mei Army went off to assist the armies of Qin in capturing Juuko city.
As a member of the first generation of Seven Fire Dragons of Wei, Gai Mou was one of the most dominant figures who ravaged the plains of China together with Zhao's Three Great Heavens and Qin's Six Great Generals. Before his incarceration, it was said that Gai Mou was responsible for taking the heads of over a hundred enemy generals. However, despite his strength, other Great Generals such as Ou Ki or Ren Pa never bothered dueling him considering the fact that he lacked something worth fighting for, which limited his true potential, and made him unworthy of a monster such as Ou Ki, who stated that he would be worthy of being sent to the next world in a duel once he found that sentiment.
Gai Mou has monstrous strength and wields a big glaive in battles. Due to his destructive power, he easily slain multiple soldiers and So Sui in a single stroke. His dueling prowess was great enough to overwhelm Shin in their duel as the strength of his blow being compared to Ren Pa.
As a great general, Gai Mou is a capable leader and is able to command men effectively in battlefields.
Due to his dense nature, it is assumed that Gai Mou is not skilled with tactical strategies. He often leave that to his strategist, Jun Sou.
- [Monologue about Shin]
"It's not because this kid is an accomplished glaive wielder. If anything, due to how shallow his technique is, you can tell he only just took it up in the last few years. But this boy possesses something that more than makes up for it. His Boldness! Just what is he carrying on his shoulders?!" (Chapter 384, page 15–16)