Shirō was born in 1621 in modern-day Kami-Amakusa, Kumamoto as the son of Catholic parents, Masuda Jinbei, a former Konishi clan retainer, and his wife. Urban legend speculates that Shirō could have been the illegitimate son of Toyotomi Hideyori, but these claims have little credibility. Portuguese Jesuit missionaries had been active in Japan since the late 16th century. By the age of 15, the charismatic youth was known to his Japanese Catholic followers as "heaven's messenger". Miraculous powers were attributed to him.
Rebellion
Shirō was among Japanese Catholics who took over Hara Castle in a rebellion against the Shogunate. They mounted a coordinated defense that held off attackers, but the rebel force had no logistical support, and their resolve was weakened. Shirō was said to display posters in the castle to raise morale and said:
"Now, those who accompany me in being besieged in this castle, will be my friends unto the next world."
One of the rebel soldiers,, betrayed Shirō. He got a message to the Shogunate that rebel food supplies were becoming strained. The Shogunate forces made a final assault, taking Hara Castle in the process. The Shogunate forces massacred almost 40,000 rebels, including women and children. Yamada, who betrayed his fellow rebels, was the only recorded survivor.
Death
Shirō was taken captive and executed after the castle was overtaken. His head was displayed on a pike in Nagasaki for an extended period of time as a warning to potential Christian rebels. Many Japanese Catholics consider Shirō as a folk saint.
Honors
A statue of Amakusa Shirō was installed at Shimabara Castle.
He was popularized as the main antagonist in the 1967 Futaro Yamada novel Makai Tensho, in which he is resurrected from the dead and is hunted down by Yagyū Jūbei Mitsuyoshi. It was adapted as a motion picture, Samurai Reincarnation, an anime, Ninja Resurrection, and a film, Samurai Resurrection.
Shirō is featured as a character in the light novel Fate/Apocrypha and its adaptions, serving as a Heroic Spirit under the Ruler-class Servant in his 17-year-old form. He is also one of the summonable Ruler-class Servants in the mobile game Fate/Grand Order, albeit event-limited. Most of his historical details carry over to the game's lore.
He is the central antagonist in the Japanese manga XBlade by Satoshi Shiki.
In the manga Amakusa 1637, Shirō is not executed but is enslaved by the mentally unstable time traveler Naozumi "Kotaka" Yatsuka, who sees him as a stand-in for his unrequited love Natsuki.
In the videogame saga Samurai Shodown, Amakusa is one of the main antagonists. Having lost his faith in the Christian God, Shirō fell in despair and made a deal with the demon Ambrosia, possessing one of Hanzo's sons to incarnate. Later in the series, he is defeated and his evil villainous side is permanently slain, restoring his virtuous side. He sacrifices himself to help the heroes defeat Ambrosia.
In the videogame Live A Live he appears as a spirit and is one of the enemies of the Secret Orders chapter.
The character Amakusa Shougo from the anime Rurouni Kenshin was based on Amakusa Shirō. He and his followers are rescued from the Hara Castle siege by the protagonist and a Dutch ambassador and exiled to Holland.
The Gundam manga Crossbone Gundam: Skull Heart and its sequels feature a Mobile Suit powered by a clone of original Mobile Suit Gundam protagonist Amuro Ray's brain known as the Amakusa, referring to Amuro's Japanese heritage; he is martyred at the end of '.
In the anime series The Kindaichi Case Files, Hajime Kindaichi went to the fictional Amakusa Island, where Amakusa Shirō rumoured to have hidden gold in a treasure cave.
One of the antagonists in La Blue Girl is a character called Kyoshirō, who bears a strong resemblance to Amakusa Shirō.
Amakusa Shirō is also featured as one of the antagonists in the anime Ken'yū Densetsu Yaiba.
Amakusa Shirō was featured in the videogame Monster Strike.
In the Japanese Light Novel series, A Certain Magical Index, one of the factions is called the Amakusa Church. Their base is stated to be located somewhere in Kyushu, possibly in or near the town Amakusa. The Amakusa are usually seen fighting the Roman Catholic Church.
