Genba Kazama is a thief of notorious reputation operating in the Shinano region, recognized for his exceptional skills in deception and infiltration. He is almost always seen wearing a fox mask crafted from a special type of clay, which he can reshape at will to alter his appearance completely, allowing him to mimic the faces of others.

His background is rooted in the Kazama clan, a branch family of the Suwa. His father was a loyal retainer who mastered various espionage and disguise techniques in service to his lord. Tragically, these very skills led to accusations of cowardice and theft, resulting in the family's disgrace and expulsion. Genba inherited his father's techniques, his name, and the cynical principle that money is the only thing worthy of trust. This history of betrayal and social rejection forged his pragmatic and guarded worldview.

In terms of personality, Genba outwardly presents as a lecherous, greedy, and mischievous individual who professes to believe only in money. He enjoys playing pranks, making lewd gestures, and harassing others, often serving as a source of crude comedy within the group. Despite this flamboyant and unscrupulous exterior, he is shrewd, highly capable, and possesses a set of internal principles. He is not overtly loyal in a traditional sense, but his actions demonstrate a deep-seated reliability when those he respects are in genuine danger. His cynical motto implies that everyone has hidden, selfish motives.

Initially, Genba has no interest in joining the protagonist's cause. He is approached on the recommendation of Suwa Yorishige to help steal an important imperial document. Viewing the young leader as a naive noble, Genba agrees to help only in exchange for an extravagant future reward of an entire province. However, during the mission, when their escape is threatened by enemy pursuers, the young leader throws himself into danger to protect Genba. Deeply moved by this act of sincerity and sacrifice, Genba abandons his plan to flee alone and uses all his tricks to ensure their mutual survival. After this incident, he formally joins the group.

Within the group, Genba's role is that of a versatile operative specializing in infiltration, sabotage, intelligence gathering, and unconventional tactics. He is a master of disguise and deception, capable of fabricating explosives and formulating clever escape plans. Although he can be a source of internal chaos with his eccentric behavior, he proves to be an indispensable asset in critical situations. His key relationships are marked by a unique dynamic, such as his forcibly established partnership with a captured enemy girl, whom he manipulates into helping him manufacture bombs.

Genba's character development is most evident in the shift from a self-serving mercenary to a genuine, if still cynical, comrade. While he never fully abandons his love for money or his crass habits, his actions demonstrate a growing investment in the group's survival and success beyond mere financial reward. His abilities are numerous and centered on what could be considered proto-ninja arts, including change of facial appearance, advanced stealth techniques, evasion, theft, sabotage, and some skill in crafting explosive devices.