Regulus Black

Ok as we all have guessed, regulus could be the RAB from the note, but is there more to him than we realise. What is his background? Who actually is he?

Quote :

"Sirius jabbed a finger at the very bottom of the tree, at the name Regulus Black. A date of death (some fifteen years previously) followed the date of birth.

"Was he killed by an Auror?" Harry asked tentatively
"Oh no," said Sirius. "No, 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. From what I found out after he died, he got in so far, then panicked about what he was being asked to do and tried to back out.

What was it that he was being asked to do and why did he back out? Is he really dead? Whose side was he really on?

I think he was a deatheater and then turned to the good side after he saw all the crap that Voldemort was about. I wonder if Voldemort tried to get Regulas to be the one to murder Harry or the Potters or something like that. Or maybe he was asked to be the one to go after the Longbottoms. It had to have been a really bad thing he was asked to do.

I think it was becasue somebody else ((Bella maybe)) realized what he had done so she killed him. Or he got the horcrux and returned to the good side and he was ordered to be killed. Maybe he was pulling a Snape and being a spy

I think that at first he was evil then turned good and realized what he had done I think that it is he whom got the locket and tryed to destroy it remember he said I will probably be dead when you read this so he knows that voldemort will find out.
I also think that it is Regulus who is R.A.B. because it needs to be someone whom has been mentioned before like the half blood prince.