Transformation.
She is a normal Tiefling. A pale pinkish color of the skin, short horns, yellow eyes, and a soft humble smile that sweetly greeted those around her, and a personality that makes anyone fall in love with her, Until any blood moon. Twice a year during a 24 hr period, she transforms. Her horns grow thicker and longer towering over her head. Her skin turns from pale pink to blood red and her eyes turn black with red pupils. The soft smile turns into a devilish grin revealing her sharp fangs. Twice a year she hides away, ashamed of her transformation.