This article's content is accurate to the most recent public game version, 0.4.8d.
This article contains lore not currently mentioned in-game, but which will be expanded upon in later updates.
Haruka was a distant ancestor of Yoshida, the first of the family line.
Backstory
Haruka was born somewhere in Japan many centuries ago, some time in the Sengoku period. At some point in her life she contracted with a Kitsune, becoming a mystic ninja. As Kitsune are Youkai, a type of fair folk, Haruka can be considered to be one of the many precursors to the modern Magical Girls, and indeed performed many of the same duties.
The descendants of Haruka would continue her work throughout the centuries, contracting with Youkai to fight against monsters like the Magicos. Even after the family eventually emigrated from Japan to Brazil their work continues, as can be seen in Yoshida who has become a modern day Magical Girl.