There are five of the four Houses of Hogwarts, which is common sense.
So it’s no surprise to be in Azkaban at the start, right?
When William opened his eyes, he found himself in Azkaban.
Soon after a fellow inmate named Mundungus was released from prison,
Strange things happened,
A unique job fair is suddenly held.
“What, Hogwarts recruits professors?”
“Come to Azkaban?”
“Professor of Defense Against the Dark Arts?”