Black Ice

Daughter of the God of the Underworld, Hades. Half mortal, Half goddess. Hair black as the darkest night and eyes as cold as the hardest ice.
Hades had a tryst with a mortal (no surprises there), except this mortal wasn't the same as other mortals. She was a witch. It was only fitting to call the child after one of the feared Titans, Theia. Hades couldn't help but chuckle when he found that out. When a mortal woman gives birth to a daughter with extraordinary magical abilities, what is she to do? Consult Albus Dumbledore, of course. Dumbledore took the child under his tutelage, helping her control her magic from a young age. The girl truly was extraordinary, she didn't need a wand or even to speak incantations, she simply put will to what she wanted, and it was done. Theia wasn't even deemed fit to attend Hogwarts until she was 17, fully mastering her powers and controlling her emotions. Despite her hard features, Theia was soft and kind, although with a short temper and a mischievous side. While it was hard to get her angry, when she was it was best to back up, as often times her hands would burst into the Blue Flames of Hades, which burned hotter than any fire that could be summoned by wizards. Some even say that the flames were reflected in her icy blues, giving her a slightly demonic look. She didn't mind that. She, after all, was literally the spawn of Satan.