Yamashiro was born to a human woman in Sasaki who had an affair with an Inugami Yokai, and like most other Hanyo he had a tough life growing up.. His mother was already in a bad spot barely making money to live and having Sasaki didn't make it much easier until he became a child. When he was about 9 years old he started to steal food and money from others to slowly support his mother and himself more, and as she got a job they actually started to be somewhat well off for a while. Yamashiro continued to steal and eventually it became natural for him to appraise stuff he saw to find what would make him money quickly..

Eventually his stealth got the attention of some less than savory people who wanted him to start doing better paying 'jobs', so they taught him what it meant to kill someone for money.. becoming a hitman of sorts, branching out into many forms of crime for a while.. Fraud, theft, assassinations and the like. After a couple of years he started to suspect something, his past few jobs have all been targeting a rival group and he started to notice less and less activity form them, more so than his actions would cause. One day while he was taking care of his mother who has aged a lot over the years due to being just a human..

They were attacked by the group he's been slowly destroying under the orders of the people who hired him often.. Not being the best at hand to hand combat, preferring quick and stealthy kills, they easily overwhelmed Yamashiro and beat him to near death.. But this triggered apart of his Yokai blood.. His animal features got more feral as his eyes turned a deep red color, his fangs and claws growing as he started to slice the throats of the people attacking his home, but like all Yokai who become this feral state, he didn't know who or what he was attacking before it was to late.. When he finally managed to regain his senses he looked around to see that he did manage to kill the gang attacking his home, but he also killed his mother in his feral state.. The only family he has known and the one he started to do all of this for..

Not wanting to stay in his house any longer, he gathered up whatever he could for memories of his life and his mother before he burnt the house down.. all of the bodies and his mothers still inside.. it is around this time when he gained the attention of the Reaper, the personification of death.. The two of them struck a deal, The Reaper would give Yamashiro the powers to perfect his craft of stealth and murder so he can kill the ones who made him go down this dark path when all he did before was steal.. And Yamashiro would kill whoever Death told him to as long as they were not his friends or a new family.. Under this agreement Yamashiro would spend the next 230 years doing as Death said, and as he wanted to.. keeping to Sasaki as a well known danger no one could find "Shi no hauru" the Howl of Death..