In the Chamber itself, we see a large statue of a wizard, which Harry presumes is Salazar Slytherin. We also meet Tom Riddle, who is, as it turns out, the heir of Slytherin. Present only in spirit, he has all the same been controlling Ginny, and having her act as Slytherin's heir.
In the 1942 to 1943 school year, Tom Riddle, an Heir of Slytherin, opened the Chamber of Secrets in order to complete Slytherin's "noble work".
Is Hermione The Living heir of Slytherin? Her real parents were Daneel and Dean Novak, Pureblooded wizards. Turns out Daneel was Tom Riddles younger sister, Daneel Riddle. Of course, the Riddles were related to Salzar Slytherin himself, and this made Hermione the living heir of Slytherin.
A manifestation of Tom Riddle reveals that he is Lord Voldemort and the Heir of Slytherin. He previously opened the Chamber and framed Hagrid. He has been using the diary to possess and control Ginny, who had been behaving strangely.
Harry is the Heir of Gryffindor (though his powers have been bound by his father when he was a baby), Neville is the Heir of Hufflepuff, Meghan (OFC, daughter of Sirius) is the Heir of Ravenclaw.
Horace Slughorn: The current head of Slytherin House, Horace Slughorn has been teaching on and off at Hogwarts for quite some time.
He is proud
Pride is a key Slytherin trait, and arguably Albus has it in cauldrons. Sometimes this is to his advantage, like when he takes pride in having a friend like Scorpius Malfoy, who is funny and clever and kind, no matter what the rumours say about him and his parentage.
The Heir of Hufflepuff was none other than Cedric Diggory, who was well on his way to fulfilling the prophecy of the Heir of Hufflepuff when he was tragically murdered by Peter Pettigrew.
Harry Potter came very close to being sorted into Slytherin before he persuaded the Hat to sort him into Gryffindor. Yet the spectre of Slytherin haunted him for some time afterwards, becoming particularly potent in Harry Potter and the Chamber of Secrets, when he was rumoured to be the heir of Slytherin.
Moaning Myrtle
Born in the late 1920s to Muggle parents, Myrtle Warren started her Hogwarts life in the early 1940s, where she was sorted into Ravenclaw.
Harry himself is a half-blood, since his pure-blood father, James, married a Muggle-born witch named Lily, and his maternal grandparents were Muggles.
Hagrid knows Voldemort's name, identity and past.
Voldemort's past, as revealed by the books, is shrouded in mystery and guesswork. In fact, at the beginning of the series, barely anyone but Dumbledore and Hagrid knew that Voldemort was the charming, successful Tom Marvolo Riddle.
In the warehouse, Grisha explains that she was a student with Riddle at Hogwarts, who along with Wiglaf Sigurdsson and Lazarus Smith were the true heirs of the Hogwarts founders (Gryffindor, Slytherin, Ravenclaw, and Hufflepuff, respectively). The heirs formed a club dedicated to "making the world a better place".
Salazar returned to Hogwarts in 1026 only to find Helga Hufflepuff had passed away three years prior. After a visit to Helga's grave, Salazar entered the Chamber of Secrets for the last time and peacefully died in the underground mausoleum, clutching a photo of him and Helga together.
If Harry had been placed in Slytherin, it would have altered his path drastically. It's doubtful, for example, that he would have developed such a strong friendship with Ron and Hermione. Although that's not to say that he would have got on with Draco Malfoy, either. He was, after all, the worst.
Unfortunately, that man was the Bloody Baron, who was head over heels with Helena, and stabbed her in a rage when she refused to come home. After Helena was tragically killed, legend tells us that Rowena Ravenclaw died of a broken heart.
Salazar married a witch named Nerezza of Aosta. They had two children: Maximiliana Slytherin Argent and Cenric Slytherin. Salazar Slytherin founded Hogwarts School of Witchcraft and Wizardry with Rowena Ravenclaw, Helga Hufflepuff, and Godric Gryffindor in approximately 993 A.D.
Gryffindor's often thought of as the best house, as it's the focus of Harry's time at Hogwarts. Hufflepuff is stereotyped as a house for pushovers and Ravenclaw for bookworms. Finally, Slytherin is thought of as the 'evil' house.
Though the Sorting ends up plaguing Albus Potter all through school as the only member of his family to set foot in Slytherin, he's there for a reason. And that reason has nothing to do with lineage or attributes or inclination. He just wanted to spend all of his time with Scorpius Malfoy. So he did.
Scorpius Malfoy
He joins Hogwarts at the same time as Albus Potter, forming an unlike friendship on the Hogwarts Express. This grows when the two of them are sorted into the same house, Slytherin. Unlike Draco, Scorpius focuses his Slytherin-like determination into his studies, being an avid reader.
Albus is the younger brother to James Sirius Potter and the older brother to Lily Luna Potter. He is also the husband to Adelena Delacour and later on the father to Alexis Potter and Savanna Potter.
The Head of Slytherin is Horace Slughorn (who left the role to Severus Snape for fifteen years before taking it up again in 1996) and the House's patron ghost is the Bloody Baron.
The statue of Salazar Slytherin in the Chamber of Secrets depicts an "ancient and monkey-like" man with a "long thin beard that fell almost to the bottom of his sweeping robes." His beard was white in colour. Marvolo Gaunt, a blood relative, is similarly described as being monkey-like in appearance.