It's one of my host's letters. He writes them to his only companion in his youth, now long gone.

Amane Bakura-chan.

He writes them, even now... though they're as boring as ever. Letters to the dead. That loneliness of his is like a pit of despair in his heart.

Somehow you've managed to dull that loneliness... along with at least one or two others. But it seems he can't forget.