Harry Potter while at the black ancestral home. He came across research that Sirus's brother had been doing before he was murdered. It came as a shocking revelation that Dumbles has been hiding his true colors since before he met Harry. Dumbles was the one to betray his parents. Pettigrew became a unwilling pawn on both sides of the coin. Dumbles made sure that the abuse that heaped onto him from his relatives got more violent as time went on.. Dumbles did have wards on the house, but those wards were in place to make Harry's live as miserable as possible. The ward also had an unexpected consequence that Dumbles never realized. It became sentient the moment the power came on.