Jiro Osamu was the body double for the original, aging Mr. Unknown, Japan's vigilante protector. His master would take part in the detective work while Jiro would fill in for any physical work Mr. Unknown would be required to take part in. But with the villain Lord Death Man appearing in Tokyo in order to kill all of it's Super Heros, Jiro's master is murdered, leaving him to take on the full time role of Mr. Unknown.
Mr. Unknown was created by writer Grant Morrison, first appearing in issue #1 of Batman Incorporated, drawn by artist Yanick Paquett. Mr. Unknown was the first of many "international Batmen" that Morrison used in his new concept of Bruce Wayne's global franchising of the Batman identity.
Jiro originally was essentially the backup to his master Mr. Unknown, but after the death of his master, he would attempt to take on the mantel of Mr. Unknown in order to help Batman. Instead of continuing to fight crime as Mr. Unknown, Jiro would be drafted into Batman Incorporated as the Batman of Japan.
Major Story Arcs
Batman Incorporated, Mr Unknown is Dead!
When Batman started his new crime fighting venture, Batman Incorporated, his first priority was to travel to Tokyo, Japan with Catwoman to recruit Japanese crime fighter Mr. Unknown. Unbeknownst to Batman, Japanese villain Lord Death Man had set out to kill all Japanese crime fighters and captured Mr. Unknown. After melting Unknown's hands off, Lord Death Man breaks a container of acid over his face, killing him. Just after the moment of Unknown's death, his "body double" a young man by the name of Jiro walks in on the murder. Escaping Lord Death Man and his henchmen, Jiro goes into hiding.
When Batman and Catwoman arrive at Unknown's hideout, they come across the body and Lord Death Man's henchmen. After fighting them off, Batman interrogates the henchmen, demanding to know who they were waiting for. Batman finds out about Jiro and goes on the hunt for him.
Soon afterward, Jiro's girlfriend calls him to her apartment. There, Jiro finds her tied up with Lord Death Man behind her threatening to snap her neck. Jiro points a gun at Lord Death Man who taunts him to break his "code of honor." Jiro fires twice at Lord Death Man, hitting him and sending him out a second story window. Jiro's girlfriend cries out as Lord Death Man was the only one who knew how to stop the trap that leaves her plummeting into a pool with a giant octopus. Batman and Catwoman arrive to the scene, and with Batman busy fighting off the henchmen, Catwoman is left try and save the girl, despite her hatred of water.
After the situation at Jiro's apartment is solved, Jiro's talks to Batman and informs him that while his boss, the original Mr. Unknown only did detective work due to his age, he was his body double and did all the physical aspects of the crime fighting job. He wants to accept Batman's invitation in order to honor his master, but Batman declines, citing the fact that he used a gun.
Still wanting to prove himself to Batman, and carry on his master's legacy, Jiro dawns the Mr. Unknown costume in an attempt to try and help save Aquazon, Lord Death Man's next target. When he arrives to the scene of the fight, Jiro saves Aquazon but ends up getting shot by Lord Death Man in the process.
Japan thinks that their greatest crime fighter Mr. Unknown is dead, and mourns their loss. But little do they know, Jiro faked his own death, because he wanted a fresh start, he wanted to be reborn. Batman acknowledges Jiro's goal to join his ranks, and offers him a three month probational period in order to see what he's made of, under a new identity, the Batman of Japan. Jiro is last seen in a Batman costume, fighting off one of Japan's super villains - Karmak, the Professor Gorilla from the Batman manga.
Most recently Jiro was seen in a new costume and identifying himself as "Batman Japan". He is currently dating Shy Crazy Lolita Canary. They most recently teamed up to battle Lady Tiger Fist.
Jiro also recently assisted Batman in his trip to Hong Kong in the Batman Eternal series. Jiro tells Batman of the massive gang war in Hong Kong between the forces of Carmine Falcone and crime boss Shen Fang.
Jiro Osamu is named after Jiro Kuwata, who wrote the Batman manga on which Mr. Unknown is based on, and Osamu Tezuka, famed Japanese cartoonist who created Astro Boy and is credited with popularizing both manga and anime.