I guess it's about time to post this.
Name: Obsidian Flare.
Appearance: A unicorn mare with a brown coat blackened by exposure to extreme heat, a fiery red-and-orange mane and tail, grey eyes that seem to glow slightly, and a volcano cutie mark.
Age: Physically, in her early twenties, but chronologically over three centuries old.
Sex: Not for a very long time, if at all.
Skills: Manipulation of earth is Flare's primary power. She can tunnel, reshape rock, or alter tectonic forces so as to create earthquakes and volcanic eruptions with her magic. In addition, in her long time spent in a volcanic chamber, she has built up a high tolerance to heat.
Personality: Flare is calm and patient, but very determined. Because of her power and the things she has endured, she can be detached and arrogant at times, and put herself above others. She's also prone to forgetting common customs and using more force than needed. Still, she ultimately means little harm, and is remarkably sane after her long imprisonment underground.
History: Long ago, Flare was an normal pony with a strong talent for earth magic, which she used to help miners in the lands around her town. However, as she used her powers, they grew, and as her powers grew, so did her arrogance. She even compared her power to that of the Princesses, as they had the power of the sun and moon while she had power over the earth.
Soon afterwards, a small band of ponies who feared that she might attempt a takeover joined together to defeat her. One of the leaders, Starfire, wanted to kill her for her insolence, but the other, Dream Vision, thought that doing so would be unjust, and instead opted to seal her away in a volcanic cavern. Unfortunately, after the sealing, the band was broken apart by infighting, and although Dream Vision had intended for the sealing to be temporary, she could not release her.
Three hundred years passed. Flare lay in her chamber, forgotten, waiting for a liberation that never came. Finally, she got the idea to create an earthquake that would strike the nearby town of Bridle Shores, attracting startled ponies who would seek to find the source. Then, when they came, she would explain her situation and attempt to convince them to help her.
Her plan worked well. Several parties journeyed underground to investigate, and within a week, she was released. She has since taken up residence at Heavy Metal Ironworks, and the consequences of releasing her are yet to be seen.
Relationships: Being cut off from society for so long, she doesn't know many ponies that well, and all those who she once knew are likely long dead. However, she has been acquainted with Gearstride and Silverpine, and also has a bit of fondness for Blades, Arvadraa, Night Jewel and Zaros, who released her.