Dean Thomas

Dean Thomas was a Hogwarts student in the same year as Harry Potter. He is one character that J.K. Rowling has not been able to develop as fully in the books as she has in her imagination.

Early life
Dean's background is not fully explored in the books, but J.K. Rowling revealed on her website that, although he is in fact the son of a wizard father and a Muggle mother, Dean grew up thinking he was a Muggle-born. His father left when Dean was very young, never telling his wife that he was a wizard, out of the belief that not knowing the truth would protect her. He was later killed by Death Eaters when he refused to join them.

Dean's mother remarried a Muggle, Mr. Thomas, who raised Dean as his own son after the death of Dean's natural father. Dean lived with several half-siblings in London and was stated by J.K. Rowling to have had a "very happy home life."

Hogwarts
The arrival of a letter for Dean from Hogwarts caused Mrs. Thomas to suspect that Dean's father may have been a wizard. Dean started at Hogwarts on September 1, 1991 and was sorted into Gryffindor house, where he became friends with Seamus Finnigan and the Weasley twins. He was a supporter of the West Ham football team and was good at drawing.

Dean Thomas was one of the first to arrive for the inaugural meeting of the group that became Dumbledore's Army in 1995 and his support for his friends does not appear to have faltered.

Sometime around the end of his fifth year, Dean became romantically involved with Ginny Weasley, who he dated well into his sixth year. That same year, he also replaced Katie Bell as the Chaser for the Gryffindor Quidditch team after she was hospitalized for touching a cursed necklace. His relationship with Ginny began to go downhill after he laughed when Harry Potter was hit with a Bludger and because Ginny felt he was overly solicitous with her. Harry may have have contributed to their split while under the influence of Felix Felicis, a good luck potion, which caused Harry (who had developed an interest in Ginny himself) to bump into Ginny while under his Invisibility Cloak. Fortunately for Harry, Ginny blamed Dean. According to Harry and Ginny's friend Hermione Granger, their relationship was already rocky at the time, and this fight ended it for good.

On the Run
Dean's presumed [Muggle-born]] status put him on the run from the Ministry of Magic in 1997, when it felt under the control of Lord Voldemort and began rounding up Muggle-born wizards and witches, imprisoning them in Azkaban for allegedly stealing magic.

At some point, Dean joined a group of fellow runaways — Muggle-born wizards Ted Tonks and Dirk Cresswell, and goblins Griphook and Gornuk. They were overheard once by Harry, Hermione and Ron; Dean expressed worry at hearing that his former girlfriend Ginny had gotten in trouble back at Hogwarts as well as the belief that Harry was fighting Voldemort.

Later, the group of fugitives were found by a group of Snatchers that seems to have been led by Fenrir Greyback. Dean and Griphook were the only survivors of the violent capture. Around the same time, Harry Potter triggered the Taboo curse on Voldemort's name, alerting the Snatchers to the trio's location. Harry, Ron and Hermione were also captured, and the prisoners were all brought to Malfoy Manor, Death Eater headquarters. All of them but Hermione — who was tortured with the Cruciatus Curse by Bellatrix Lestrange — were imprisoned in the dungeons in the basement, where Luna Lovegood and Mr. Ollivander were already held.

However, the group was soon rescued by Dobby the house-elf, who was fatally injured shortly after successfully transporting them to the home of Bill Weasley and Fleur Delacour. Dean spent the next few months at Shell Cottage with Luna, Griphook and the trio; he and Luna seemed to grow close during this time, though as with Harry and the others, Dean appeared bemused by some of her comments.

Dean returned to Hogwarts when his fellow D.A. members signaled for help when Harry, Hermione and Ron returned and the Death Eater army prepared to attack the school. Although he had lost his wand, he managed to find one eventually and participated in the Battle of Hogwarts. The trio, beneath Harry's Invisibility Cloak, saw Dean and Parvati Patil fighting against Antonin Dolohov and stunning another Death Eater at one point.

As Dean is not mentioned among the casualties, he presumably survived the Second Wizarding War. Nothing is known about his later life.

Seamus Finnigan
Fellow Gryffindor and roommate Seamus Finnigan was Dean's best friend. The two grew close in their first year and continued to be so throughout their time at Hogwarts. Unlike Dean, Seamus initially believed the smear campaign the Ministry of Magic and the Daily Prophet ran against Harry Potter when he claimed that Voldemort had returned, but this does not appear to have affected their friendship. Seamus was displeased when Dean was chosen as the replacement Chaser for the Gryffindor Quidditch team when Katie Bell was injured over himself, but again, the two remained close friends. When Dean returned to Hogwarts in 1998 to fight in the final battle, Seamus was ecstatic to see him, and ran to hug him.

Ginny Weasley
Dean started dating Ginny Weasley, a Gryffindor student a year below him, around the end of his fifth year. Ginny's brother Ron disapproved of the romance, as demonstrated by his furious reaction to stumbling upon the couple kissing passionately in a deserted hallway. They appeared to be very closed at first, but, according to Ginny's friend Hermione, things began to get rocky as Ginny became displeased with Dean for what she perceived as overprotectiveness, as Dean constantly tried to assist her in everything. Harry contributed to their ultimate break-up by bumping up against Ginny when she and Dean were going through the portrait hole while under his Invisiblity Cloak and after having taken Felix Felicis. Thus, luck was on the side of Harry, who had developed an interest in Ginny, and she thought Dean was trying to push her through the portrait. This row led to their split.

Ginny clearly got over Dean soon after they broke up, as she began dating Harry soon after and admitted to him that she had never really given up hope that the two of them might be a couple. Dean, however, seemed astonished and hurt when he saw Harry and Ginny kissing, and went as far as smashing his glass, indicating that he took their split harder. Later, while Dean was on the run and heard news about Ginny, Harry noted that Dean was concerned for her welfare.

Physical description
Dean was described in the American edition of Harry Potter and the Philosopher's Stone as a black boy who was even taller than Ron Weasley. J.K. Rowling explained on her website that the reason this description was left out of the British edition of Philosopher's Stone was that her editor "thought that chapter was too long and pruned everything that he thought was surplus to requirements."

Behind the scenes

 * A drawing at one time posted on J.K. Rowling's website revealed that Dean's first name was "Gary" in early drafts of Philosopher's Stone.
 * Rowling included information on Dean's background in an early draft of Harry Potter and the Chamber of Secrets, but ultimately cut it out, as she felt it was an "unnecessary digression." She stated that she had to a certain extent traded Dean's "voyage of discovery" for Neville Longbottom's because the latter character's discoveries about his past were more relevant to the main story.
 * Rowling said that when it came time for casting the film adaptation of Philosopher's Stone, she told director Chris Columbus about Dean, and that she thought he was "slightly taken aback" by how much she had developed the background of such a minor character.