Mystia Lorelei is a night sparrow youkai from the Touhou Project series, first appearing as a stage boss in 'Touhou 8: Imperishable Night.' She is known for her ability to confuse humans with her singing and often runs a stand selling grilled lamprey. Mystia is a playful and mischievous character who enjoys interacting with both humans and other youkai. Her role in the series is generally that of an antagonist or mid-boss, adding challenge and charm to the story’s encounters.