Zachary Kralik

Zachary Kralik was a vampire on Buffy The Vampire Slayer.

Before becoming a vampire, Zachary Kralik was a mental patient and serial killer. It was revealed he had killed his own mother. He was sired by a vampire who was amused by his deeds as a human and felt he was worthy of being a vampire. Of course he continued his carnage and without a soul did a lot worse. He was shunned by other vampires because of his mental state and hatred for his mother, who is hinted to have abused him emotionally and perhaps sexually.

Zachary was then used by the Watcher's Council as a test for Buffy on her eighteenth birthday. They would weaken her and place her in a room with him and she would have to defeat him using her brains and wits. Unfortunately he escaped from his cage and killed two people, one being sired as a vampire. He kidnapped Buffy's mother, but she was still able to trick him into drinking a glass of Holy Water with his pills, killing him instantly.