In Okayama, the "Kurotani"'s family wasn't a samurai but a pedigree of ninja.
"Tenryu" has been training of ninja since childhood as the fifth son of the "Kurotani"'s family.
（"Tenryu" is youngest brother.）
At the time of that training, his father cut his face from the forehead to the left cheek.
"Tenryu" was at the age of five.
And thanks to such a hard training and genius talent, became the best warrior among the five brothers.
He was above his brothers in physical ability and technological skills as of the age of about ten.
Youngest brother "Tenryu" couldn't eat adequately in his family.
However, it seems that he had eaten the missing part by using the ninja technique in the nature, from childhood.
It seems that such things were also growing the physical ability and technological skills of "Tenryu".
In such a situation, he begins to hate his father who imposes hard training.
In addition, he was harassed by jealousy from his brothers, and he began to hate his brothers.
And as his father grows old, he gets stronger than his father.
Still his father imposes hard training, so he strengthens hatred.
He was brought up freely because he was a youngest brother.
That thing might have strengthened the opposition against repression.
And when "Tenryu" became 16 years old, his mother as the only understanding person died of illness.
"Tenryu" triggered it, killing all the remaining families.
Incidentally, from this time he began to hurt himself, the number of men he killed.
After that, "Tenryu" went to a wandering journey without a destination.
On that journey, "Tenryu" meets a certain person.
And, under the influence of that person, "Tenryu" decides his own direction.
When "Tenryu" is 21 years old, he will arrive in Edo.
He will participate in "Roshigumi" which was just made at the same time.
"Roshigumi" is the predecessor of "Shinsengumi".
"Tenryu" decided to put himself on the side of the shogunate.
"Tenryu" was the strongest among the soldier of "Roshigumi", so he was assigned to assassination work.
Actually, the assassination that "Roshigumi" and "Shinsengumi" did was mostly done mainly by "Tenryu".
If "Tenryu" isn't there, "Shinsengumi" may have been buried in history.
Also from such a thing, "Tenryu" had a great presence and influence in the organization.
But he won't engage in any political activities of the organization.
Thoroughly, he chose to be a murderer.
And when "Roshigumi" came to Kyoto it changed name "Shinsengumi".
At the same time, "Tenryu" becomes captain of the 0th party to do assassination work in "Shinsengumi".
There is no member in the 0th party.
Actually, "Roshigumi" was partly split at this time.
However, "Tenryu" who decided to put himself on the side of the shogunate remained in "Shinsengumi".
After that "Tenryu" continued to kill people as captain of the 0th party in "Shinsengumi", currently his body has about 150 scratches engraved.
"Tenryu" didn't kill people indiscriminately.
Of course, in case of unavoidable work or to protect myself, he also kills those who don't feel worth it to kill.
But other than that, he killed those he felt worth it to kill by himself.
By the way, all but the scratch of the face cut by the father are due to self scratches.
In short, "Tenryu" has been killing about 150 people.
"Tenryu" never appears on the center stage, because he want to reasons for kill people at "Shinsengumi".