the heaven beside me

10000 years ago the demon king yumekui died in a bloody battle between the heavenly peak and the devildom. Another 1000 years passed in peace without blood spilled.
but then one day while being on a mission kaori founds a beautiful girl in sealed in the ice.
Mesmerised by her beauty he approaches the ice and touches it.
as soon as the ice was touched the ice melt.
Who could have known that that incident would mean the devastation of the 3 realms