Disclaimer- I don't own Inyuasha.
Her master was very powerful, Kirara knew. She was very wise, but very powerful. Full of righteous fire and justice, yet love and friendship.
Demons hated her master. She was strong, too strong. But no demon could match the power of the priestess.
And even if they could, she was there, protecting her master.
They were together, all the time. Companions, both of them. She had raised Kirara, taught her, nurtured her, trained her.
Together, they were invincible.
Until that day.
The demons came, in scores, in droves, in mobs, slathering and slobbering and stinking, all roaring for her master's blood.
Dragons, ogres, serpents, wolves, all demons of all shapes and sizes, merging and transforming, trying to overpower her master.
But they fought, the two of them. They fought as they never had before, synchronized, perfectly in tandem, slaughtering demons by the dozens.
And for seven passes of the sun, they were successful, driving off demon after demon, destroying them.
But demons were not foolish, and they were strong.
They merged, always twisting and transforming, becoming more and more horrible, more and more terrible with time.
And soon, soon Kirara could no longer hold her own, and was grasped in the terrible coils of a great serpent.
And as her master charged, slicing into the scales of the demon, she was ambushed.
Oh, that terrible moment when her master's chest was pierced by the demon's fangs, and the demon's howl of triumph, terrible and screeching.
She tried to fight free, but it was far too late.
By then, the priestess had made her final choice. With a sad smile towards Kirara, her faithful ally, she cast away the demon's soul...
And her own.
With that one movement, a bright shining light began to glow from her chest, and a single glittering orb burst from her breast.
The Jewel of the Four Souls. The Sacred Shikon Jewel.
But none of that mattered... her master was gone.
Kirara wept and roared, for both were the same thing. Her rage and grief was great, and for a long time, she slept at the base of her master's body, turned to stone by her efforts.
People came and went, time passed, and nothing mattered.
But one day... a girl came into the cave. She was curious, wondering in that way that only a child can.
She looked much like her master... her raven hair and her kind, loving eyes.
So when the girl picked her up, she didn't fight.
And for the first time in years, left the cave with that girl.
Kirara would learn that the girl's name was Sango, and became her protector, her ally. But Sango was never her master.
But a friend, she was.
Her time with Sango was pleasant, but there seemed to be something missing.
And then the Others came. The monk, the child demon, the girl, and the half demon.
Much like Sango, they each, in their own way, reminded her of the priestess.
The monk was lecherous and silly... but beneath it, he was wise.
The child demon was innocent and young... but full of a well of friendship.
The girl was naive... but her heart was pure, full of love.
The half demon was brash and angry... but deep within, righteous and just.
And then, at last, Kirara felt complete.
The idea that Kirara was also there, helping Midoriko battle was only touched on once, one of many potential storylines I feel weren't extrapolated on enough.