Mine Sasaki's grandfather worked for a Japanese electronics company when he came to the United States to start their first US office in Seattle.  It was not long after he'd started the branch when his own son was born, making him the first of the Sasaki family to be a native born American.  He followed in his father's footsteps, taking over the family business and learning the family style of Karate, Musabetsu Kakuto Ryu Kenpo.  He married the daughter of one of his father's friends, who then immigrated over from Japan.  However, he was not aware of the Oonishi clan's true history.

When his wife, Mine's mother, came over to American, her sister, Sayuri "Sarah" Oonishi.  She, like many before her, followed in the family tradition of practicing Onmyodo, a form of Japanese sorcerery with roots in the Chinese Taoist traditions.  Not being married herself, she took it upon herself to make sure the family tradition was carried on by teaching her niece the secrets of Japanese spirit magic.

Mine's mother, Aika, never objected to Mine learning karate from her father, but having her own daughter's head filled with Sayuri's superstitious nonsense put a strain on the sisters' relationship.  However, Sayuri continued Mine's training in secret while also tutoring her on Japanese history, customs and language.  This turned out to be a good thing when an old Sasaki family enemy sent an Oni to kidnap her parents and younger brother.  Sasaki was able to use her combined training in Karate and Onmyodo to escape the evil spirit and get to her aunt for help.  Together with suhubo (grandfather), they were able to rescue their family.  The sleep spell the family had been put under ensured that none of them ever knew what really happened.

It was later, while Detective Adsila Lowrey was investigating a strange occurrence of murders that Mine and Adsila met for the first time.  By this point, Mine's training had reached the point where her aunt had informed her of certain rules that come with learning Onmyodo.  One of the chief of these is that when someone is troubled by evil spirits, Mine was obligated to provide what help she could.  Well, in this case, a school friend was being troubled by vengeful ghosts who had been killing the children of the families that had caused his death.  Adsila had been hired by one of these families and when the two crossed paths, they managed to share notes, find and finally banish the restless ghost.  

Since then, Mine's had an after-school job at Mrz. Lowrey's detective agency as the office clerk/secretary.  Her parents do not know that Mine frequently "consults" on cases involving spirits or Asian myths and monsters.

Being only 17 and having her rather unusual upbringing has put Mine under a bit of pressure different from that of most of her classmates.  Her main problem is her desire fulfill her obligations as an Onmyogi while maintaining an image of respectability and normalcy for her mother.  Her father is much more forgiving of her tomboy nature and her grandfather and aunt are both proud of her sence of duty and dedication in her quest to master not only the demanding discipline of Karate but also that of Onmyodo.

However, with so much focus placed upon the weird and supernatural, Mine remains a mystery to her classmates.  She never seems to have time for normal things like shopping, dating, movies or video games.  As a result, she remains rather nieve about the normal aspects of life and doesn't understand why her family thinks it's so important for her to hide the fact that a 5' 1", 100 pound girl can kick the snot out of any boy in her school.

Mine's abilities come from two primary areas.  First are the skills she's learned practicing the family form of Karate, Musabetsu Kakuto Ryu Kenpo.  She's incredibly advanced for someone as young as she is, even having mastered her Ki to the point where she can resist knife blows with her bare skin.

On the other side, she's mastered several Onmyodo spells.  In order to use her magic, Mine must inscribe the spell using special inks on prepared pieces of parchment.  By placing the parchment on her target and incanting the activation phrase, she releases the magic contained in the scroll.  It takes her several hours to prepare each scroll (even longer for some of the more complex spells), but her aunt is amazed that the grasp her niece has on the fundamentals of magic.  Her aunt has also given her a pendant that glows whenever spirits are nearby.

Note:  Mine's magic pool has the Spell limitation from page 246 of Fantasy Hero.  For those without that book, here is a summary of what is contained within that limitation:
* Cannot be used in Multiple Power Attacks
* Cannot be Bounced or Spread
* Cannot be used with the following maneuvers: Blazing Away, Grab By, Haymaker, Hip Shot, Hurry, Move By,
  Move Through, Pulling A Punch, Rapid Fire, Snap Shot, Suppression Fire or Sweep