In the corner of Natsume's bedroom, there is a small box. It is made of cardboard, frayed at the edges, damp in the upper left corner. It takes little effort to move, weight spreading evenly along the bottom.
There is only one thing inside the box, the only thing that is solely Natsume's. No one alive has ever seen it.
Natsume intends to keep it that way.
He opens the box every once in a while, late in the night, or early in the morning, when Nyanko-sensei is out drinking, when Touko-san and Shigeru-san are sleeping.
He has no memories of his mother, precious few of his father, but somehow he can remember this, the feeling of his own hands in his father's hands as together they open and close the box.
Natsume only opens the box a little, never leaving it fully open, as if the air will taint the contents inside, and perhaps it will. His eyes are good enough that he can make out the faint black marks on yellow paper.
Once a year he takes the sheets out of the box, the day he is told was her birthday, exactly at midnight, and he reads.
He reads exactly one hundred pieces of paper, sets them aside carefully and lovingly, as if they had been written in his own hands, taken hours to craft and mold into more than a compilation of words.
Each paper then goes back into the box, perfectly in order, edges aligned, no corner out of place.
The next hour Natsume recalls each and every letter, beginning with a Dearest Reiko, ending unsigned. He thinks of love and youkai and things without a name and wonders if this is what Reiko had to believe in, if this is why she lived.
Natsume thinks of Touko and Shigeru, Nishimura and Kitamoto, Taki and Tooru. He thinks of Nyanko-sensei and Misuzu, Hinoe and Hiragi, Tama and Kai.
Natsume has more than enough to live for.