Born to two renowned heroes, Felix Helmont was thought to be destined for greatness. His father, Marcus Helmont, was a famed fiend-slayer. His mother, Karen, was a genius and powerful wizard. Every monster, fiend, and villain in the land cursed their name. Felix himself was a gentle child, never prone to anger or violence. He merely wished to become a writer, and contribute to his community in ways other than heroics.
Everything changed the night his father rode out to confront the fiend Veldius. Felix was sick with fever, so his mother stayed behind to care for him. News arrived the next morning that Marcus Helmont was victorious against the fiend, though it cost him his life. After his father's death, Felix began to have strange dreams. Eventually, they became nightmares. He could feel an evil presence in his mind. When it revealed itself to him fully, it called itself Nocturnus.
Nocturnus tormented young Felix at every opportunity, threatening to punish him for "his father's sins." At times, Nocturnus was even able to take control of the young boy and cause him to harm himself or others. Felix's mother researched every magical ritual she could find to save her son. She brought him to clerics, to doctors, to other mages. Nothing could exorcise the mysterious fiend. Despite the risks, she tried teaching Felix magic, both arcane and divine, hoping he could succeed with his own attempts. It only served to make him more dangerous.
Felix grew older and more difficult to control. Tired, broken, and left with no choice, his mother had him committed to an asylum staffed by powerful mages. They promised her they would find a way to set Felix free. Instead, they began to research him and the fiend inside him. Felix knew he had to leave as soon as he realized their plan. Using every trick and spell he had learned, he was able to escape. When he awoke the morning after he fled, he was sleeping underneath a dead tree. Beside him was a note, clearly addressed to him from The Master of Castle Ravenloft. It was an invitation to a dinner at his castle. Though there was no date, it simply said "Become worthy of this invitation. You will know when the time is right." The letter also promised, above all things, "An answer to all your questions."
He set out for a way to reach the castle, relying on other peoples' goodwill. He traveled with caravans, and traders. Every day he prayed, and studied, and kept Nocturnus at bay. He researched as much as he could about the castle and its master. He even joined an adventuring company, in hopes of raising money and building connections. His fellow adventurers soon became friends, and gave him some brief measure of peace. Alas, everything else would have to wait. He has a goal now, and he is driven.