The decision to write
Albus Dumbledore was surprised, to say the least when he was informed of the news. Quite possibly one of the most intriguing pieces of news he'd ever received.
It was a rather dreary, cloudy morning. In the midst of preparing Hogwarts for its upcoming semester, he received a letter from the Ministry of Magic.
The letter carried the fragile news of the existence of Voldemort's son. It was a wonder how such a boy had escaped being noticed for so many years of his life. After all, he was already fifteen. The Ministry of Magic only recently become aware of his existence by the means of one of the boy's distant relatives.
It was apparent the child had no idea who his father was; he was in Japan- orphaned.
Naturally, it is of utmost importance to get the boy to Hogwarts as soon as possible. If they could manage that, they could keep the boy away from his father. Perhaps even keep him from ever even knowing who his father is.
Albus tosses the letter into the fireplace, gathering his thoughts.
Once he'd thought long and hard enough about the words to write and send, he sat down and began writing a letter addressed to Dazai Osamu.