Kaori's grandmother was once a quite adventurous human girl who left her hometown of Lan-Feong to explore the south-western Melosian continent. She gained a reputation there as the Lavender Thunder, for her skill at magic and fighting prowess. It has been implied that she met Balase Stock-Lamont there before she met Bruno, her future husband.
When they returned as a wedded couple, she soon gave birth to a son who later married a Danuki saleswoman with a troubled past. Kaori was born of this union and for a while happiness reigned in their family. Yet when a landslide claimed Kaori's parents, Linsha Ri and Bruno were left with their orphaned granddaughter. Years later, Kaori struck out for the lands where her grandfather had been raised and met Damast. When the two of them finally made it to Lan-Feong for their wedding, disaster struck.
Linsha-Ri had been struck by a deadly trap in her youth, one that spewed thin wooden stakes. While she and Bruno thought they had removed all of those, one had managed to slip through and lodged on the outside of her lungs, damaging internal organs over the years and giving her shortness of breath. Eventually this led to organ failure and for a while she was dead until the selfless Tsukomogami Par-rite brought her back enough for an unorthodox cure to take hold.
Having her internal wounds treated with Demonic Energy rich Ureonggaksi slime caused her to transform into one, albeit with her original black hair colour and eastern eyes. Her aging was also slightly reversed, leading to speculations among her family. After Perry's resurrection as a human, she and Bruno adopted him as per request and are working hard to raise him properly.
She's also spent time learning to utilize her new form, being very quick on the uptake to the extent that she now has coated her home and those of her extended family with plaster based off of Ureonggaksi shells that can sprout spikes at a touch.