Xiao Rai is a Ronin Samurai who defected from his country along with his brother Leng Rai. Together they started a mercenary company called Hack N' Slash Mercenary Company which has a front located in Falador.
Xiao was born on the eastern island of Ren Bo, which is located in the northern part of the Scythe. His family consisted of his mother, father, and his older brother Leng.
Xiao and his brother learned their fighting tequniques from a nameless master. He taught them the art of fighting with a katana as well as fighting with weapons from the west. Unlike his brother, Xiao specialized more in lighter western weapons.
After saving up enough money between him and his brother, they decided there was more opportunity in the lands to the west. The night of their departure they buried their katanas knowing that they would be taken from them during customs. Without telling anyone they boarded a ship and made their way through the dangerouse sea to Port Phasmatys. They knew they would never be able to return to Ren Bo because they had become traitors.
Welcome to the West!
Upon arrival, Xiao and his brother made their way to Varrock where they had custom steel weapons made for them. Since the blacksmiths didn't know the arts of making a katana he settled for two scimitars. He later painted them red so that they would match his armour.
After completeing a couple of jobs for variouse clients the brother saved up enough money too rent out a space to live and conduct their own mercenary buisness out of.