Regulus Black

Regulus Black (1961? - 1979) was the son of Orion and Walburga Black and the younger brother of Sirius Black, Harry Potter's godfather. According to Sirius, he had joined Lord Voldemort's Death Eaters, then panicked at the seriousness of what he was asked to do, and tried to back out.

Regulus has played little part in the events of the Harry Potter stories so far, but it is widely believed that more information about him will appear in the final book. In Harry Potter and the Half-Blood Prince, Harry and Albus Dumbledore are searching for one of Voldemort's horcruxes but instead find that the original has been replaced by a fake containing a message to Voldemort: To the Dark Lord

''I know I will be dead long before you read this but I want you to know that it was I who discovered your secret. I have stolen the real Horcrux and intend to destroy it as soon as I can. I face death in the hope that when you meet your match you will be mortal once more.''

R.A.B. [src]

Regulus is considered the most likely person to have written the note.

Life and Times
Information about Regulus comes from only two, rather sketchy, sources. Sirius had fallen out with his family, and then spent considerable time in Azkaban prison, renowned for destroying the minds of its inmates, but he told Harry:
 * He was murdered by Voldemort. Or on Voldemort's orders, more likely, I doubt Regulus was ever important enough to be killed by Voldemort in person. [src]

J. K. Rowling donated a copy of the Black Family Tree to a charity auction, which provided information about the year in which Regulus was born, and when he died. It showed that he died in the same year as his father.

Sirius also noted that Regulus was exactly the opposite to himself, in the eyes of his parents. Although Sirius was the older son, he disagreed totally with the traditional views of his family, and as a result left home while still at school. On the other hand, his parents regarded Regulus as an ideal son. Voldemort was seen as standing for the cause of pureblood supremacy over other wizards and muggles, and this idea was firmly supported by the Blacks. As a result, they generally approved when Regulus became a death eater. However, unlike other members of their wider family, Orion and Walburga were not themselves death eaters.

Towards the end of his life, Orion had lived in considerable fear, and spent every knut he could on magical defences for his home. As his death seems to have coincided with that of his son, it has been suggested that it may have been related to Regulus' break with Voldemort. The picture of Regulus' mother in the family home at 12 Grimmauld Place seems demented and screams repeatedly about 'filthy half breeds'.

Regulus' cousin Bellatrix Lestrange is shocked and infuriated in Order of the Phoenix when Harry Potter tells her that Voldemort is a half-blood. It may be that Regulus, with similar beliefs to his cousin, was similarly shocked to discover that he had dedicated himself to the cause of a halfbreed becoming ruler of the wizarding world. Regulus becoming hunted by Voldemort is consistent with his father's concern about security, his mother's comments and the coincidence in the death years of himself and his father.

Evidence that RAB is Regulus Black
See R.A.B. for further information.

The Harry Potter Lexicon briefly posted a claim that a reliable source had confirmed that Regulus' middle name was Arcturus. This claim shortly disappeared, and was replaced by one simply saying'' 'Well, this has been interesting. And it gets more interesting by the moment','' but without any retraction of its accuracy or other explanation.

The founder of HP lexicon, Steve Vander Ark commented on another website, the Leaky Cauldron, that:
 * Obviously, Jo is the source of this information. When have you ever known me to post rumours as facts? It's from Jo. That doesn't mean she talked to me directly, of course, but I do know that it came from Jo. I honestly think that Jo figures she's already told us that it's Regulus. Read the Melissa/Emerson interview. I think she would be surprised that this is even an issue. I have asked permission to reveal who told me. If they say I can, I'll let you all know. Otherwise, feel free to take this with whatever grain of salt you need to.
 * Steve

Derivation of name
In Latin regulus means 'little king'. As a name it has also been applied to the star alpha leonis, which is situated at the heart of the lion in the constellation of Leo. The Black family seems to have a tradition of naming its members after stars.