This impurity cannot be exorcised

Fifteen years previously...

A man, hovering on the edge of death, exchanged his child with an aberration to buy his life.
He received "All-Seeing Eyes" from the aberration as proof of their contract.
He had to return them and annul the contract.
If he didn't, his child would be killed by having his skin flayed when he reached fifteen years of age.
His father died without telling anyone where the eyes were.
A countless number of aberrations were congregating all around the protagonist.
The freakish girl, flashing a friendly grin. The crows who called him their brother. The maiden in the scarlet kimono.
The sinister person wearing a kitsune mask. The aberration tempting him to become aberrant himself.
And the insects that continued to buzz.
Would he be able to find the eyes?
And would he be able to escape his fate?
At last, the day he turned fifteen was arriving.

You, sir, are the child born just to be killed by having your skin flayed.