unspeakable 

An Unspeakable is a wizard or witch who works in the ministries of magic's department of mysteries. Little is known about their workplace, and even less is known about their jobs. Employees of the Department of Mysteries are forbidden from discussing their jobs or disclosing any information about their department, hence the name "Unspeakable."

Obliviator

An Obliviator is an employee of the Ministry of Magic tasked with keeping the Wizarding world hidden fromMuggles, as per the Statute of Secrecy. Obliviators perform Memory Charms on any Muggle witnesses who happen to see something they should not, such as seeing a magical creature. Mnemone Radford was the first Obliviator to work for the Ministry.