"My parents are Muggles, mate. They don’t know nothing about no deaths at Hogwarts, because I’m not stupid enough to tell them."
-- Dean Thomas (OP11)
Dean Thomas was a “half-blood” Gryffindor boy from London in Harry’s year at Hogwarts.
He was a classmate of Harry’s and best friends with Seamus Finnigan (GF7). He was a black Londoner (JKR) who grew up as a Muggle, and thus had always been a fan of the football (U.S. soccer) team West Ham United (PS9). At Hogwarts, Dean and Seamus tended to goof around in class a bit (CS6), and both were quite friendly to Harry (PA8). Dean’s home life was kept fairly separate from Hogwarts, and he didn’t tell his parents much about what goes on at school (OP11). He dated Ginny Weasley for a good portion of his sixth year (OP38), but they broke up over petty disagreements (HBP24).
When Harry began being attacked by the Ministry, Dean quietly sided with Harry, despite Seamus being an outspoken critic, and joined Dumbledore’s Army (OP16). He clearly admired Harry for publishing his story in the Quibbler (OP26), and later told other wizards that he firmly believed Harry to be the Chosen One (DH15).
Dean’s father was actually a wizard, though he never told his family this as he feared for their safety. When Dean was a young boy, his father was recruited by Death Eaters and killed when he refused to join, though Dean always thought he had simply walked out (JKR). As a result, when the Ministry began rounding up Muggle-borns, Dean went on the run (DH15). He was captured by Snatchers, until Dobby, Harry, Ron, and Hermione helped him escape to Shell Cottage (DH23). He stayed there, becoming friends with Luna Lovegood (DH25), until returning to Hogwarts to join in the battle against Voldemort (DH29). In that battle, Dean duelled Antonin Dolohov and knocked out at least one Death Eater (DH32).
Joined Dumbledore’s Army (OP16)
During his 6th year he dated Ginny Weasley until she broke up with him in May of 1997 (HBP24)
Dean's parents are both Muggles and he has a number of brothers and sisters. The family is a happy and supportive one (JKR).
However, Dean's blood status is not quite what he believes it to be. His biological father was actually a wizard who walked out on the family when Dean was very young, then was killed by Death Eaters when he wouldn't join them. His "father" is really his stepfather and his siblings are stepbrothers and sisters. Dean's mother never knew the truth about Dean's father (JKR).
Dean is good at drawing (PS), and also "good with the quill" (i.e. can forge signatures) (PA).
Dean derives from the surname Dean, from Middle English dene/Old English denu (meaning "valley"). It can also come from a person who either was the dean in a cathedral or someone who worked for a dean (Internet Surname Database).
Thomas is a surname derived from the given name Thomas, which comes from the Greek form of the Aramaic name תָּאוֹמָא Ta'oma', meaning "twin". The popularity of the name in England is attributed to Saint Thomas Becket, a 12th century archbishop of Canterbury (Behind the Name).
J.K. Rowling's comments on Dean Thomas (from her original website)
Dean Thomas's background
Anybody who has read both the American and British versions of 'Philosopher's Stone' will notice that Dean Thomas's appearance is not mentioned in the British book, whereas in the American one there is a line describing him (in the chapter 'The Sorting Hat').
This was an editorial cut in the British version; my editor thought that chapter was too long and pruned everything that he thought was surplus to requirements. When it came to the casting on the film version of 'Philosopher's Stone', however, I told the director, Chris, that Dean was a black Londoner. In fact, I think Chris was slightly taken aback by the amount of information I had on this peripheral character. I had a lot of background on Dean, though I had never found the right place to use it. His story was included in an early draft of 'Chamber of Secrets' but then cut by me, because it felt like an unnecessary digression. Now I don't think his history will ever make it into the books.
Dean is from what he always thought was a pure Muggle background. He has been raised by his mother and his stepfather; his father walked out on the family when Dean was very young. He has a very happy home life, with a number of half-brothers and sisters.
Naturally when the letter came from Hogwarts Dean's mother wondered whether his father might have been a wizard, but nobody has ever discovered the truth: that Dean's father, who had never told his wife what he was because he wanted to protect her, got himself killed by Death Eaters when he refused to join them. The projected story had Dean discovering all this during his school career. I suppose in some ways I sacrificed Dean's voyage of discovery for Neville's, which is more important to the central plot. (JKR)
The role of Dean Thomas is played by Alfred Enoch.
Lexicon list of Chasers
From the Web
Harry Potter Wiki: Dean Thomas