Hello -- TenthWeasleyWriter here with your requested review!
Having once thought of writing a Regulus/OC myself (and having actually planned it out, too, though it never came to fruition), I was very interested to see this appear in my review thread. I've seen many different takes on Regulus, and still yours is different from others I've read. I think it's intriguing that you write about his joining the Death Eaters as a way to protect his family, and I'm curious as to how that particular plot point will develop down the line.
Because this is only the prologue, as you have marked it, I don't think there's much to be said for plot development at this point. Admittedly, I don't read a lot of Death Eater fics, and since I'm writing a fic around this same era I generally steer clear so I can keep my ideas mine, if that makes any sense. However, this does seem like an interesting first chapter, and I think you've managed to hook potential readers to the rest of your story well. :)
The dialogue, though rather sparse, was good! I think not everyone can write a house elf's voice well, but I saw no problems there. The only thing that sounded a bit off was referring to Kreacher as an 'it' instead of 'he.' Although not a human, Kreacher is referred to in the books as a he, just as Dobby is a he and Winky is a she; that's something to consider altering. ;)
As for characterization, I think Regulus, Voldemort, and Kreacher were all written rather well. My concern is for Sirius, who never talked in canon about his brother with any measure of kindness, even going so far as to refer to him as an idiot. What I might suggest is altering Sirius's letter, and have it a bit less... brotherly, if that makes sense? Unless Regulus's rejection of Sirius's help is what makes him think he's an idiot, and that's something a reader can't glean from this. If that's the case, well, ignore this. :D
Overall, a very promising start! Minus the few bumps that I pointed out, you do have a nice prologue here, and I think it sets up the arc of your story with a fair amount of fluidity. Good job! And thank you for requesting a review from me!
Author's Response: Hi! Thank you for the review.
Sorry that it took me so long to answer it.
The reason why I'm using 'it' and not 'him' when talking about house elves has actually a reason. While more enlightened wizards undoubtedly saw house elves equal to their own race, I'm betting that the ancient pureblood families weren't exactly as most broad-minded with their views.
Hence using the 'it' as belittling term at this point of story.
Sirius's letter seems to divide readers quite effeciently. Some of you like it a lot, some of you not. Interesting.
I've been considering Sirius's character while writing this, so you just have to wait and see how his views change with time. I do believe that since Sirius had ability to love and hate people with equal passion, he often saw things very black and white. I would even go as far as suggesting that might have been one his biggest character flaws. =)
Ah well, but thank you very much for taking time and reading prologue. I appreciate it very much.