Wow, absolute brilliance. Never in a million years would it have occurred to me to develop Cadogan's character in this way, or to pair him with Helena. But there really is a logic in the two of them together. You've done such a wonderful job of demonstrating how good they could be for each other that the tragedy of it all is utterly heartbreaking. My silly, romantic side likes to think that they still have several more centuries to sort things out, though…
You write Helena, Cadogan, and the Baron in such a way that they really feel like relics of their time. You write a damn good Tom Riddle, too. Really, is there anything you can't do?? ;)