Dementor Dementor is a minifigure from the theme , based on the creature of the same name from the books and films . To date , two variations of Dementors have been released . Description . Original Design . The Dementor design features a sand green skeleton torso and arms . Exclusive to this minifigure is a piece attached to the bottom of the skeleton torso . This is a sand green short rod with two clips at the top and space for a stud to fit underneath . The Dementor has a sand green head , of which the only facial feature is a gaping , open mouth or hole , through which " The Dementor ' s Kiss " is delivered . On top of the head is a dark grey hood and underneath the head is a cloak of the same colour , ripped at the tips . 2010 Redesign . In 2010 , a new version of the Dementors was made for 4842 Hogwarts Castle . The 2010 redesigned version is more detailed and instead of having light green skin , has a dark grey skeleton torso , and arms . Attached to the bottom of the torso is a light grey short rod with two clips at the top and space for a stud to fit underneath . Additionally , the Dementor has a double sided grey head with a more open mouth , a black hood , and a black cape ripped more at the bottom . In the Video Games . In both " " and " " , Dementors appear mainly in their original design , with a light green skeleton torso and arms and a dark grey cloak and hood . However , they also appear with no cloak , a black hood , a grey skeleton torso , and a white shining face . In both games , Dementors can be defeated only by using the Patronus Charm , and when attacking can immobilise the player before damaging them . Background . Dementors are described as tall hooded figures in black cloaks , with scabby , clammy hands . They have rattling breaths , and seem to spread cold and negative emotions . Beneath their hoods , their face consists of more scabby skin , shallow indents where eyes would usually be and a single hole where a mouth would normally be . This hole is used to suck the soul out of a person . It is unknown what is underneath a Dementor ' s cloak , and it does not appear that there is any known way to kill them . However they can be repelled effectively with a Patronus Charm , which produces a silvery shield which guards against Dementor . Dementor are said to breed like fungi , in the cold , damp and dark . They are invisible to Muggles . Dementors feed on happy thoughts and memories , and this is also how they move around , as they are blind . If given the chance , a Dementor will perform the ' Dementor ' s Kiss ' on a person . This ' Kiss ' is how the Dementors suck out someone ' s soul , leaving the victim as an empty shell , considered by many as being worse than death . This punishment seems to be the British wizarding equivalent of capital punishment . Harry Potter first learned of Dementors in his third year . Sirius Black had escaped from Azkaban , and the Dementors were looking for him . Harry encountered one on the Hogwarts Express ( causing him to listen to his mother and his father ' s last words before Lord Voldemort killed them 12 years earlier ) , and he fainted because the Dementor was particularly attracted to him because of his troubled past . Professor Lupin used a Patronus Charm to send it away . The Dementors had been posted at the gates of Hogwarts , and in the nearby village of Hogsmeade , in order to capture Black if he came near . Harry later learned of Black ' s innocence . Then he and Hermione found Black after a brutal fight with Lupin as a werewolf at the lake only to find more than a hundred Dementors had arrived to suck out Black ' s soul . Sirius immediately fainted , leaving Harry and Hermione to fight the Dementors . Harry tried to fight off the Dementors with the Patronous Charm , but Hermione soon fainted afterwards leaving Harry alone to fight the Dementors . Harry holds his own for a while , but eventually the Dementors overwhelm him . The Dementors are about to suck out Harry , Hermione , and Sirius ' s souls , when a mysterious stranger on the other side of the lake conjures a Patronous that sends all of the Dementors away . Harry believed the man who conjured it was his father and then Harry fainted as well . Harry then goes back in time with Hermione , and goes to see who conjured the Patronous that saved him , Hermione , and Sirius . When no one comes , he realizes that he was the mysterious stranger who cast the Patronous and sent the Dementors away . Harry then cast a fully fledged patronous ( a patronous that has an animal form ) and gets rid of more than a hundred Dementors which saved Sirius , Hermione , and his past self . In Harry ' s fifth year , he and his muggle cousin Dudley Dursley , were attacked by two Dementors on their way home ( only this time instead of Harry hearing his parents , he hears Voldemort when he tried to kill him in his fourth year ) . Harry managed to cast a Patronous and send the Dementors away , and takes a sickened Dudley home . He later learns that it was Dolores Umbridge who sent the Dementors after him . In Harry Potter and the Half - Blood Prince , the Dementors have truly abandoned Azkaban and changed sides . In Harry Potter and the Deathly Hallows , Voldemort brought his army of Dementors to the Battle of Hogwarts . The Dementors attempted to suck out Harry , Hermione and Ron ' s souls , however , Luna Lovegood , Seamus , Dean Thomas , and Ernie Macmillman saved them with fully fledged Patronous and encouraged Harry , Hermione , and Ron to cast their own Patronous to send all of the Dementors away .