His ability to speak Parseltongue is why the Slytherin emblem is a serpent. Merlin himself was sorted into Slytherin when he was at Hogwarts, and the young wizard went on to become one of the most famous wizards in history.
Merlin was a wizard that lived during the medieval times and also an ancestor of Salazar Slytherin's descendant, Austin Zygo.
Probably because he was powerful and ambitious. It could also be that many of the great wizards were Gryffindors, and J.K. thought it would be fair to put one of them in a different house.
Salazar Slytherin was one of the four founders of Hogwarts School of Witchcraft and Wizardry and the least open to the idea of non-magical families sending their children to the school.
In the wizarding world, Merlin is a well-respected wizard from ancient times, whose name is often shouted by witches and wizards as an expression of shock.
Dumbledore may have been a legendary wizard, but he can't be compared to, well, Merlin, a wizard so legendary even Muggles know of his exploits. Merlin was the world's most famous wizard, and, arguably, the world's most powerful. Fellow Slytherins, you can be proud of our house— the great Merlin himself was one of us!
According to records from the wizarding world, he is thought to have been among the most powerful wizards in human history. Merlin attended Hogwarts as a Slytherin and displayed a remarkable command of the magical arts. Some claim that he is the most potent wizard ever.
The Heir of Slytherin turns out to be Ginny Weasley, who is being controlled via a magical diary that once belonged to Tom Riddle, AKA Voldemort.
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. The problem with being a female Slytherin heir, is that they're cursed.
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. Harry/Ginny, Ron/Hermione, Remus/Tonks. Sixth year. After a rare magical illness Harry becomes outstandingly powerful.
He is cunning
Slytherins are a cunning lot, and there are all kinds of examples of Albus Potter using his wiles to come up with schemes and plans worthy of any member of Salazar's house throughout Harry Potter and the Cursed Child.
Merlin himself was sorted into Slytherin when he was at Hogwarts, and the young wizard went on to become one of the most famous wizards in history.
Like Tom Marvolo Riddle (aka Voldemort), Merlin was a Slytherin, an ambitious, powerful wizard. He was a wizarding legend, and, of course, more powerful than the Dark Lord. According to the Harry Potter Wiki, Merlin was “arguably one of the most powerful wizards of all time”.
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.
Considered by many the first wizard ever, Merlin is both a Harry Pottercharacter, albeit one the fans didn't get to see in the series, and the first mythological sorcerer of all time.
Strong: Albus Dumbledore
Most regarded him as the strongest wizard in history, and even Lord Voldemort himself feared to face him. Beyond his many impressive titles and positions of power, Dumbledore exhibited absolutely extraordinary abilities on several occasions.
Albus ended up in Slytherin because he couldn't stop thinking about ending up in Slytherin, and so the Sorting Hat couldn't grasp anything other than his thoughts about being in Slytherin.
The Heir of Hufflepuff was a person foretold by the Seer Harmonthrep (Ajrand) to bring great glory and honor to the House of Hufflepuff, considered boring and lackluster by most.
He attended Hogwarts for the first time with his cousin Rose Granger-Weasley but unlike Rose, Albus wasn't sorted into Gryffindor, much to his shock and fellow Hogwarts students. The Sorting Hat actually chose Slytherin where he joined Draco Malfoy's son, Scorpius.
Ginevra Molly Weasley (also known as Ginny) is the youngest child and only daughter of the Weasley family. She is Sorted into Slytherin during Harry and Jim Potter's second year.
Myrtle's life was cut shockingly short when she was killed by the Basilisk at Tom Riddle's command.
Ginny Weasley was able to speak Parseltongue while she was possessed by Tom Riddle's Diary, which enabled her to open the Chamber of Secrets.
Merlin, also known as Myrddin Wyllt, Merlin Caledonensis, or Merlin Sylvestrus lived from about 540 to August 584. He is a figure from Welsh legend who served as a bard before ending his days as a madman, prophet and mystic in the forests of Tweeddale in the Scottish Borders.
It placed alchemist Nicolas Flamel first, since he can make unlimited amounts of gold, followed by Bellatrix Lestrange, Lucius Malfoy and finally Harry, whose fortunes came from inheritances. Ask the kids: Lestrange, Malfoy and Harry all inherited a lot of money.