Issho Arakawa is the head of the Arakawa School and holds the highest rank of shin'uchi, making him one of the most respected and authoritative figures in the world of rakugo. He is an elderly man with a stern and intimidating appearance, characterized by his spiked hair, goatee, and sharp, pointed eyebrows that are styled in a traditional Japanese art fashion. He is known for his moody and gruff personality, as well as his dogged adherence to rakugo tradition. While his demeanor can be intimidating and his actions antagonistic, he is widely respected, and his name carries tremendous weight within the profession.

Born as the first son of the Kurogane family, Issho was disowned for his vow of independence. He was educated in the Kashiwaya school under the name Kisoba Kashiwaya and also worked at a soba shop alongside Shiguma Arakawa. Six years prior to the main story, he served as the chief judge for the shin'uchi promotion exam in which Akane Osaki's father, Shinta Arakawa, and all other applicants were expelled. His decision to fail every candidate was a shocking and controversial act that caused a significant scandal, though his infamy later led to a boom in attendance at his performances. In the six years following that exam, he only promoted one person to shin'uchi: Kaisei Arakawa.

Issho's motivations are rooted in an uncompromising vision for the future of rakugo as an art form. He believes that to succeed in a modern entertainment landscape filled with movies, music, and stand-up comedy, a rakugoka must be extraordinary, not merely good or even great. His dream is to foster a generation that will carry rakugo's legacy around the world. This philosophy drives his extreme strictness; he refuses to promote anyone he deems to lack the potential to elevate the art form to compete on a global stage. While his actions, especially toward Akane's father, initially paint him as an antagonist, he is not motivated by malice but by a deep-seated and demanding passion for rakugo.

In the story, Issho serves as the primary figure of authority and the benchmark for ultimate success, as well as the target of protagonist Akane Osaki's quest for revenge. His key relationships are defined by his role as a master and judge. He is the master of Kaisei Arakawa, a talented rakugoka he has personally elevated to shin'uchi. He has a significant and complex history with Shiguma Arakawa, his former soba shop colleague and the master who would later train Akane. His most pivotal relationship is with Shinta Arakawa, Akane's father, whose dreams he crushed years ago, and by extension, with Akane herself, whose drive for vengeance is fueled by his past decision.

A significant moment in Issho's development as a character occurs when Akane confronts him after the Karaku Cup, a competition she wins specifically to earn the right to ask him about her father's expulsion. During this private conversation, he does not act defensively but instead calmly and thoroughly explains his reasoning, demonstrating that his judgment, while harsh, was not capricious. This interaction reveals a more complex and composed figure who is open about his demanding standards. He is known to be a harsh teacher who expects a great deal from his students, but for those who can impress him, the opportunities that open up are substantial. As the patriarch of the Arakawa School, his judgment and recognition represent the highest form of validation one can achieve in that world.