When developing Yagami, the Ryu Ga Gotoku Studio team wanted to create a new type of main character following the release of Yakuza 6: The Song of Life, which concludes the story of series protagonist Kazuma Kiryu.Due to the popularity of detective stories, Ryu Ga Gotoku Studio wrote Yagami as a man who would become more knowledgeable alongside the player as the game progressed.[7] In contrast to previous Yakuza protagonists, who are often only visitors to Kamurocho, Yagami was written as a civilian resident in the city, allowing his social life to be further explored.[3] Localization producer Scott Strichart said though fans might miss previous Yakuza characters, like Kiryu and Goro Majima, he hoped they would be receptive to Yagami, describing him as "his own person – super smart, a razor-sharp wit, and a guy who harbours his own flaws, too".[9] The relationship between Yagami and his ex-lover Mafuyu Fujii was changed during development because Nagoshi found the romance spoiled the thriller aspects of Judgment.[10] Following the release of the game, Sega staff felt that if there should be a sequel to Judgment, Yagami and his partner Masaharu Kaito would retain their lead roles and would still be set in Kamurocho.Strichart commented that Yagami is not a hero so he is not able to solve all these cases on his which contrast the fantasy style Persona 5 which often deals with the protagonists saving victims using their powers.Due to the character's unspecified age in Lost Judgment, Sega hopes to feature him as the protagonist at least one time again in video game form.The game's dialogue was recorded in chronological order so players would feel Kimura's voice evolving as Yagami's character develops during the story.[15] Kimura's influence in Judgment was compared to Keanu Reeves's in Cyberpunk 2077 as the Nagoshi believes the games would make extra sales as a result of their popularities.Stritchart was initially confused, believing Yagami's similarities with Kimura might be accidental but the inclusion of his lines made him realize the actor's connections.[18][19] Based on his previous knowledge of the Yakuza franchise, Greg Chun was surprised and pleased to be selected to voice Yagami in the English-language version of Judgment.[20] Yagami's voice was meant to make him sound like a "bona fide badass" regardless of language, something the localization team believed they succeeded at.[21] The actor found his work on the game gratifying, saying, "it really did require me to let go of the tricks that you use to push a performance through, and I really did need to fall back on authenticity and genuine groundedness".As a result, he claims that for the sequel "the game kind of teed me up to really be in that Yagami mindset where, yeah, I love being a detective, but some cases are real bummer and super boring."[25] Although Yagami claims that his fighting style is self taught to the point of calling it "Kamurocho School" (神室町流, Kamurochō-ryū), the creators of the game were inspired by Chinese martial arts.[28] In the original Japanese version of the game, Yagami's fighting styles are known as Flash (一閃, Issen) and Waltz (円舞, Enbu) stances.[32] Lost Judgment also features a fourth fighting style, Fists of Might, based on boxing, as part of an optional paid downloadable content pack.Yagami gains widespread recognition in 2015 after proving Advanced Drug Development Center (ADDC) janitor Shinpei Okubo innocent of murdering patient Koichi Waku.Yagami meets Shigeru Kajihira, who reveals a failed plan to take over the area around the ADDC for a land redevelopment program that was foiled when researchers claimed to have found a potential cure for Alzheimer's disease named "AD-9".He is then called by Shirosaki at the Genda Law Office whose client, Akihiro Ehara, was arrested and convicted for sexual battery, but during his court testimony he revealed he knew about the death of Hiro Mikoshiba, who he holds responsible for his son's suicide.Yagami learns from Seiryo teacher Yoko Sawa that Mikoshiba was in fact bullying Toshiro, but she was coerced by the school to stay silent.After Kuwana fakes his death in a ship, Yagami joins Shirosaki at having Ehara confess his true crime to the law, using a recording of the students that reveals that Mikoshiba was responsible for Toshiro's suicide.[51] Due to their similar jobs, Yagami has often been compared to Phoenix Wright, the main character from Capcom's Ace Attorney series, alongside backtories and has been called one of the best cops in gaming.His unique fighting style alongside his sidequests where he meets other Kamurocho residents were noted by the writer to make Yagami's character as one of the most fun parts of the game.