The main antagonist and self-proclaimed intellectual rapist of End of the Golden Witch and Dawn of the Golden Witch. She is a young detective introduced in End of the Golden Witch. A blue-haired girl estimated by Genji to be about Jessica's age, 18, she's highly intelligent and possesses a photographic memory. She's quite polite in public and shows a deep interest in mysteries. In reality, she's quite ruthless and cunning and only solves mysteries, so she can sneer at those who pose them. She does, however, possess a serious inferiority complex, since she emotionally breaks down whenever things aren't in her favor.

Spoiler

After the events of The Great Court of Illusions, Bernkastel grants Erika the title of The Witch of Truth as a reward for completely destroying the witch illusion of the 5th game.