Luna Lovegood

Keep calm and keep the secrets! A Dementor is a gliding, wraith-like Dark creature , widely considered to be one of the foulest to inhabit the world. Dementors feed on human happiness and thus generate feelings of depression and despair in any person in close proximity to them. They can also consume a person's soul , leaving their victims in a permanent vegetative state , and thus are often referred to as " soul -sucking fiends ", rendering a person an 'empty-shell'. The Dementors of Azkaban were under the employ of the Ministry until mid- , when Lord Voldemort was sighted in the Ministry, and their defection to the Dark Lord's cause became undeniable.