I've been getting some requests for info on Hasa, so here ya go! Hasa backstory!
Origins
The 108 Stars represent 108 Demonic Overlords who were banished and who escaped imprisonment and were released by an accident.
Before they were sisters, the First Generation were all missing, or rogue, ninjas who defected from their villages successfully. They had unwittingly gathered together under the banner of Ishigakure, perhaps the only village truly accepting of their lot: fiends, outlaws, the deprived; sinners by any other name just as wicked.
However, a pack of thieves was never more than just that; cut-throat wastrels and have-nots. Ishigakure offered some protection from the pursuit of their former homes and villages, but it would never be a place suited to calling home. Danger lurked in every corner, most of all the corners inhabited by so-called allies.
Chao Gai, the soon-to-be founder, was a woman intensely disgruntled by the unsavory nature of the village. Here, she commanded no more respect than a wanton harlot. Lascivious eyes stalked her every movement and lead their predatory owners on hunts which—upon the realization that their prey had fangs and claws—often ended in bloody penitence.
That lifestyle swiftly wearied her. After a few months, enough was enough. Garnering the support of those just like her, women discontented with the status quo, one hundred and eight in total, Chao Gai plotted her «Uprising». Inclusive of herself, the movement was a hundred and nine strong; but, it was better said that they were one hundred and nine weak. A rag-tag group of rogues couldn’t join together with the loyalty and camaraderie needed to overturn the establishment. Self-interest above all else, not a single kunoichi would risk her life for such a fleeting ideal. If it was to be done, then it was to be done with a great weeping, wailing, and gnashing of teeth.
And so it was, that a plan was made. It was with the assistance of a few key supporters, who would later be known by such titles as the Five Tiger Generals and Four Heavenly Kings, that Chao Gai swept her way through their quarrelsome group. By dim starlight, for nine consecutive nights, the one-hundred and eight were made to heel and reborn through fiery nirvana, no longer mere rogues, but sisters. It was neither love nor empathy nor blood that bound the 108 Stars. It was power. Unrefined and unadulterated. For as they were made to heel, Chao Gai had not requested their loyalties, she had taken them. Binding the group together through a unique tool.
Thus on that ninth night, by the light of the constellations, the first generation Stars were born. And the sentiments towards that very tool, both the catalyst of their rebirth and the law of their new cliché, were neatly bundled within its bequeathed name—the Birth Outline.
**Note: The Birth Outline is a ninja tool that binds a group together by force, absorbing portions of their chakra to fuel a seal that's placed on each member. If said member continually entertains thoughts of betraying and harm against other members within the group, the Birth Outline will activate, killing them on the spot. This is not its only function, but it is its main function.