Slytherin House

• Type: Hogwarts House
• Location: The Dungeons, Hogwarts Castle, Scotland
• Founder: Salazar Slytherin
• Heads of House: Horace Slughorn, Severus Snape
• House Ghost: The Bloody Baron
• Key Features: Entrance concealed behind a bare stretch of damp stone wall; requires a password to enter; located beneath the Great Lake.

Slytherin is one of the four Houses of Hogwarts School of Witchcraft and Wizardry, founded by the wizard Salazar Slytherin. The House has a notorious reputation, largely due to its founder's belief in Pure-blood supremacy and its tendency to produce a significant number of Dark Wizards, most notably Lord Voldemort. Salazar Slytherin ultimately left the school after a serious disagreement with the other founders, particularly Godric Gryffindor, over the issue of admitting Muggle-born students. Before leaving, he secretly constructed the Chamber of Secrets within the castle. The Sorting Hat seeks students who exhibit traits most valued by Salazar: ambition, cunning, leadership, resourcefulness, and self-preservation. Slytherins are often described as clever and determined, willing to use any means to achieve their ends. The House's emblematic animal is a serpent, and its colours are emerald green and silver. The serpent symbol is tied to Salazar Slytherin's rare ability to speak Parseltongue, the language of snakes. Due to its historical association with Dark Magic and the prejudiced views of its founder, Slytherin House is often viewed with suspicion and distrust by members of the other Houses, particularly its chief rival, Gryffindor House.

Slytherin House serves as the primary antagonist House throughout the series, representing a rival ideology to that of Gryffindor House. The rivalry is personified in the relationship between Harry Potter and his school nemesis, Draco Malfoy. The Sorting Hat seriously considered placing Harry in Slytherin, sensing the ambition and resourcefulness he possessed, but ultimately respected Harry's choice to be in Gryffindor. The House is central to the plot of Harry Potter and the Chamber of Secrets, where it is revealed that Harry can speak Parseltongue, leading many to believe he is the Heir of Slytherin. The true heir, Tom Riddle (Lord Voldemort), is confirmed to be the last remaining direct descendant of Salazar Slytherin. Many of Lord Voldemort's followers, the Death Eaters, were former Slytherin students, including prominent members of the Malfoy, Black, and Lestrange families. However, the House is not monolithically evil. Characters like Horace Slughorn show cowardice but ultimately choose to fight against Voldemort. Severus Snape, despite his cruel demeanor and past as a Death Eater, is revealed to be one of the most crucial heroes of the Second Wizarding War, acting as a double agent for Albus Dumbledore. Furthermore, Regulus Black defied Voldemort by stealing one of his Horcruxes. During the Battle of Hogwarts, the Slytherin students are initially led out of the Great Hall to the dungeons. However, a number of them later return with reinforcements from Hogsmeade to fight against Voldemort and his army. In the epilogue, Harry's son, Albus Severus Potter, is sorted into Slytherin, suggesting that the House's dark reputation may be changing in the aftermath of the war.

The entrance to the Slytherin quarters is located in the dungeons of Hogwarts Castle. A password spoken to a stretch of bare, damp stone wall causes a concealed door to slide open. The Slytherin Common Room is a long, low, dungeon-like room situated under the Great Lake. The light in the room is a distinctive greenish glow, emanating from lamps hanging from the ceiling on chains. It is furnished with low-backed, black and dark green leather sofas and armchairs with silver embroidery, and its walls are decorated with tapestries depicting the adventures of famous medieval Slytherins. A grand, elaborately carved fireplace dominates one wall. The windows of the common room look out into the depths of the lake, allowing students to observe the Giant Squid and other aquatic creatures. The dormitories are located off the common room.

• J.K. Rowling has stated that if the Sorting Hat had a voice, it would say that its “inter-house disputes are in vain and it would like them all to unite.” (J.K. Rowling interview)
• The element associated with Slytherin is water, corresponding to the Common Room's location under the lake and the serpent's fluid-like movements. (Pottermore)
• According to Pottermore, the famed wizard Merlin was a member of Slytherin House, demonstrating that the House's ambition can be used for great good. (Pottermore)
• The name “Slytherin” is a play on the word “slithering,” a clear reference to snakes. The founder's first name, “Salazar,” may refer to António de Oliveira Salazar, a Portuguese dictator, reflecting the character's authoritarian views on blood purity.