Shiro was created by writer Ron Marz and artist Luke Ross for Dark Horse Comics in the Samurai: Heaven and Earth miniseries in 2004 and Vol. 2 in 2006.
Samurai: Heaven and Earth
In Kaga Province in 1704, a Chinese army of thousands attacks a Japanese castle of barely a hundred. During the battle only two samurai are shown to survive, one being Asukai Shiro who was knocked out under a pile of rubble. The other survivor, Masahiro informs him that Yoshiko was taken by the Chinese. Shiro then acts as Masahiro's second for ritual suicide as he does not have anything to live for. Shiro then pursues the Chinese to China and battles the warlord and his small army at his fortress after learning that Yoshiko was sold to an Arab slave merchant.
Shiro follows the Arab to Paris, where he is accosted by bigoted Frenchmen at Notre Dame, he then battles three musketeers, eventually being subdued when one hits him from the back with a barrel of wine.
Shiro is then imprisoned in Bastille. He is released under the care of a Spanish Ambassador, Don Miguel Ratera Aguilar Y Aragon who plans on using him to assassinate Louis XIV in Versailles. There he learns that Yoshiko has been bought by Louis XIV, which causes him to no longer want to complete the assassination and just leave, unfortunately Louis and the musketeers don't know that and a battle ensues.
Don Miguel tries to kill Shiro after learning he will not complete the assassination, during the battle Shiro is knocked unconscious and Don Miguel leaves with Yoshiko for Spain. Shiro rides from Versailles on a horse that was given to him by the musketeers.