The Heir of Ravenclaw was an individual prophesized by the centaur Harmonthrep (Ajrand) to bring honor and glory to the House of Ravenclaw. The Heir of Ravenclaw was in time revealed to be Brian Dumbledore (Ajrand).
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. Thus, the prophecy would remain unfulfilled forever.
Harry is the magical Heir of Gryffindor (and he's also a descendent of Godric), Neville of Hufflepuff, Hermione of Slytherin and Luna of Ravenclaw.
On falling ill, Rowena sent the Baron (Slytherin ghost) to retrieve Helena so she can see her daughter one last time. But when Helena refused to come, the Baron murdered her. Helena died young and was the last known descendent of Ravenclaw.
Harry and Neville are both heirs of Gryffindor, as are all the other wizards who did the same throughout time.
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. We also meet the Monster of the Chamber, a basilisk.
Neither of them is Slytherin's heir. Although, as Dumbledore says, Harry's ability to speak Parseltongue is a skill accidentally transferred by Slytherin's actual heir, Voldemort, when he tried to kill Harry as a baby. So perhaps this is one myth with a bit of truth to it.
Wanda Maximoff (Scarlet Witch) - Slytherin
Though it is Hufflepuff that is the house best known for loyalty, once a Slytherin's affection is earned, they can be incredibly faithful.
Rapunzel - Ravenclaw
Because Rapunzel is the most imaginative Disney princess, Ravenclaw is lucky to have her. She develops her creative skills throughout her entire life while imprisoned in the tower. She also has a strong mind and is a quick learner.
It has long been theorized that Harry is the heir to Salazar Slytherin and/or Godric Gryffindor.
Credence Isn't Voldemort's Dad But He Could Be Snape's Grandpa. Before Fantastic Beasts and Where to Find Them came out, it seemed like the story's only real Potter connection would be Newt Scamander's relation to Luna Lovegood and a Dumbledore name-drop.
Makers of fine wands since 382 BC, the Ollivanders could make quite a claim to being among the oldest wizarding families.
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. She had no friends, and was bullied relentlessly because of her glasses and acne.
At Hogwarts, she, along with her sisters, was sorted into Slytherin. It is suggested in the novels that, as a student, Bellatrix associated with a group of students – including Rodolphus Lestrange, Severus Snape, Avery, Evan Rosier and Wilkes – who nearly all became Death Eaters.
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.
Loki – Slytherin
Throughout the series, this mission leads Loki to demonstrate some great redemptive moments. However, he is still an ambitious character at his core who manipulates his situation and the people around him to get what he wants, putting him firmly in Slytherin.
Stephen Strange (Doctor Strange): Ravenclaw.
Tony Stark (Iron Man): Ravenclaw.
Filius Flitwick is the Charms Master at Hogwarts and the head of Ravenclaw house. He is a very short, dwarf-like man.
Luna Lovegood
Eternal believer in Blibbering Humdingers and Crumple-Horned Snorkacks, this enigmatic Ravenclaw is one of the best friends anyone could wish for. She thinks outside the box, a trait that does her house proud.
Hermione Granger and Ron Weasley destroy the Hufflepuff's cup Horcrux inside the Chamber of Secrets—Hermione giving it the fatal blow with a basilisk fang. In the Harry Potter and the Deathly Hallows book, Vincent Crabbe inadvertently destroys Rowena Ravenclaw's diadem in the Room of Requirement via Fiendfyre.
The story of Chamber of Secrets, as you know, is that the Heir of Slytherin has returned and he's out for Mudbloods. 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.
Tom was educated at Hogwarts School of Witchcraft and Wizardry from 1938 to 1945, and was Sorted into Slytherin House, a nod to his ancestor Salazar Slytherin himself.