Shiro is white-haired, with heavy eyebrows, a short beard and wears thick corrective glasses. He is a descendant of Shō Tai,[Footnote 1] the last king of Okinawa,[Footnote 2] and according to Michael Carpenter, he knew "swordplay like Mozart knew music".
In the series
In Death Masks, Shiro is disguised as an old derelict when Harry Dresden first meets him in an alley while Dresden is being chased by a big, four-eyed, bear-like creature. Dresden tries to tell him to run. Instead, Shiro asks him to hold his glasses, and then faces the creature, sword raised, humming with power. Shiro asks Ursiel, the Creature to "Let him go". However, the Denarian refuses, and they proceed to fight, which Shiro does most elegantly. Dresden realizes that Shiro is a Knight of the Cross. After Ursiel is killed, Shiro stops Dresden from picking up the coin that falls out of the corpse.
Shiro tells Dresden that man sees faces, skin, flags, membership lists, files -- God see hearts.
Shiro agrees to be Dresden's second in the duel with Duke Paolo Ortega of the Red Court. He sets up the meeting with the mediator and the others involved for that evening at McAnally's. Shiro suggests to Dresden that it is better and always smarter not to fight. If both parties quit, then the duel over. And, that maybe Dresden is not as locked in as he believes himself to be. As a result, Dresden suggests to Ortega that they both walk, but naturally, this doesn't work out. In the meeting, Shiro negotiates a Duel of Wills to be held at Wrigley Field.[Footnote 3]
Shiro has fought many such duels, either to protect someone, or force something to leave an area, or to fight without involving others. He has fought two duels with vampires, one from the Jade Court, the other from the Black Court. He also fought two duels with Denarians, saying that they do not honor their agreements and indulged in treachery both times.
Shiro trades himself for Dresden to the Denarians.
Later, Shiro is found in the chapel at O'Hare Airport[Footnote 4] brutally tortured and nearly dead. With his dying breaths, he gives Fidelacchius to Dresden in trust until Dresden can find the next wielder. He tells Dresden to trust his heart when Dresden asked how he would know whom to give it to. He tells Sanya goodbye and that he's proud of him. Sanya kisses his head. He tell Michael that the fight is now his and to be wise. Shiro also tells Dresden that Nicodemus is afraid of him, afraid that he saw something and to not let the Denarian unmake him, and finally that taking the Shroud of Turin from Nicodemus will undo the plague curse immediately.
At the end of Death Masks, a letter from Shiro, postmarked two weeks previous, is delivered to Dresden. In this letter, Shiro shows foreknowledge about his death, as well as his illness. Knowing he would soon die anyway, Shiro gave himself up for Dresden. Shiro was diagnosed with terminal cancer. His family knew, but he did not tell Michael and Sanya.
In Small Favor, Sanya tells how Shiro found him after he threw his coin into a canal in Venice. Shiro took Sanya to Malta to meet with the Archangel Michael, where Sanya was given the sword Esperacchius and the chance to be a Knight of the Cross.