A vibrant portrait of a blue-skinned tiefling girl with an enigmatic expression, her eyes glow with a mystical light reminiscent of the cosmos. Her face is adorned with intricate demon markings, enhancing her ethereal beauty. Her lush horns, elegantly curling and glistening with subtle iridescence, frame her face like a crown. Her hair flows like liquid night, blending into the otherworldly atmosphere. The rich colors and stylized brushstrokes emulate the sophisticated aesthetic of arcane art, infusing the piece with an anime-inspired dynamism. This cosmic tiefling, a dreamlike fusion of fantasy and celestial energy, embodies the unique allure of a demon girl with oni-style horns, a guardian of hidden realms and secrets untold.