Well, I know you hear this a lot, and it certainly sounds like a weak excuse at best, but... my father is really just misunderstood - as are the Fae, but that's a different matter altogether.
Well, in fact, I only recently learned about my father's past myself. I was too small at the time of his downfall to remember anything about it, and so I grew up believing him to be nothing more than a simple blacksmith. It was only when I grew older that I started to notice things and ask questions.
As you may know, the northern provinces of the realm used to be an independent nation before the arrival of the Red Fleet. The Order of Rendall all but annexed us and called it an "alliance". My father was one of the noble children that were exchanged to seal the pact that bound us to their fate, and spent the better part of his teenage years in the southlands, receiving the training of a proper knight of the Order. He never forgot his roots, though, and stayed loyal to the principles of his family.
Unlike the Southerners, people in the North have lived in peaceful if wary coexistence with the fair-blooded. Unlike the Order, who regards them as little more than demons that ought to be slain on sight, we treated them as neighbours. That was one of the reasons for the arrival of the Red Fleed, I suppose. That, and our mines.
It all started to go terribly wrong when my grandfather tried to forge a peace between the Order and the Fae. The time seemed right for it: in the Southlands, the fair folk had become little more than a memory, and so the old animosities were not as pronounced as they used to be. It also helped that they aided us against a common enemy, the brutish raiders who threatened the trade roads to the south. So my grandfather pledged my father's hand to one of their princesses, to show our allies from the Order that he was determined to see it through.
At that point, two unlikely things happened:
The first was that my father actually fell in love with his arranged bride, my mother. And the second was that the Order actually seemed to consider the option of making peace with their ancestral enemies.
So our family journeyed to the Citadel, in the very heart of the realm, to change the course of history once and for all. Those were golden days, full of hope of a brighter future - and I was its embodiment and symbol. What fools they were, to believe that they could escape the fate of their ancestors!
At first, it seemed as if the negotiations were proceeding splendidly. But then, everything went wrong: we don't know what happened exactly, but the order claims that a group of fae had smuggled weapons into the palace to assassinate the leaders of the Order. And indeed, the Grand Prefect and several others were slain, along with my grandfather and most of the supposed assassins. Neither my father nor my mother were present at that time, but accusations were raised against my mother anyway. An inquisitorial court pronounced her guilty of conspiracy and treason, and sentenced her to death. They did not want to draw my father into the process, though, feeling that they needed him to assure the loyalty of the north. So they silenced him by insinuating that the Order might declare me abomination, fair-blooded as I was. There was nothing he could do, no way to escape. His own wife believed him a traitor to everything they believed in, as he did not try to defend her. She burned at the stake, cursing my father by invoking the marriage vow that bound them together. I think it was that moment that broke my father at last. He actually tried to save her from the pyre, struggling with the guards in front of a crowd that was screaming for my mother's blood. But when he reached her, it was already too late. All he could do was give her a merciful death, to rob the onlookers of their cruel spectacle. He lost his sword hand in the process, and he sees that as a sign of his curse: it was the hand that was sworn to protect her.
After that, my father returned to the North and took me with him; the Order did not trust him, and there were several men in his entourage who were supposed to keep him under constant surveillance and take my life if he should try to rally against them. But my father would never be their puppet, even if it meant forsaking his station once and for all. We escaped with the help of a few loyal friends, taking refuge in a small miner's village a the utmost ends of the Northland, where he assumed the life of a common blacksmith.
Soon, news of Morrigg the Traitor was all over the realm. The Order pronounced him in league with the Fae conspirators, a slayer of friends and family. And the Fae believed him a traitor as well, feeling that he should have died rather than allowing his wife to be killed.