Mainly, it's because Valyn embodies everything I find irristable in a man. He's elegant, refined, chivalrous and gallant. Almost like an Arthurian knight. He has a strong sense of justice, and what's rigth and wrong. And yet he's aloof, distant and even a little cold. He can be condescending, and holds himself a bit apart. He projects as somewhat unattainable image, and yet he feels so much. He's full of warmth and compassion, but none of it comes through. That's a combination I cannot resist.
Also, physically he is what I find ideal in men. (pointy ears aside) He's tall and lean, which is my preferred body type. And yes, I do have a special place in my heart for men with long blond hair and aristocratic features.
Despite the fact that many people claim he was nothing but a minor, static character, I am forced to disagree. He was a developing character, and if it weren't for him, the halfbloods would have been wiped out.
I also hold firmly to the beleif that Valyn Hernalth is not dead. No, I have no solid evidence to back up my assumption, but I don't really care. There is, theoretically, a couple of different ways he could have survived. For detailed explanations, just check out my fan-fiction. And I have come across very small little hints in Elvenblood. Some people may say I am grasping for straws, but as a writer I understand the subtlty of overshadowing and allusions. I'm just saying that you never know. After all, there are two more books. But even if Valyn doesn't make a reappearance, I will not change my mind. He is still alive, somewhere.
