The first time he noticed it Kakashi had no idea how long it had been there for. He had stopped checking for a mark when he was ten years old, too busy with the notion of fighting against his father 's fate to think about a possible future with some ephemeral possibility. So at sixteen years old when he finally pulled his mask down far enough to inspect the mark on the right side of his neck, he was almost startled to see that it was no longer the blank circle it had always been.