Long post incoming.
After spending all day at school thinking about it (instead of actually… y’know… schooling), here’s Thunder Blitz’ story:
He was born in a relatively small town, with his mother being that of a unicorn and his father a pegasus. They used what little money they could afford to send him to a flight camp in Cloudsdale. He earned his Cutie Mark after flying during a storm and was struck by lightning – somehow surviving the shock and fall – and dragging himself back to a hospital. His talent was that of tenacity, and is able to take a large amount of pain without even getting hurt.
At the age of 19, finally graduating, he noticed his parents didn’t show up to the ceremony. He was mildly ticked off, and he began the trek back home alone. When he arrived, he saw the house was on fire, and a firepony on scene told him what had happened: the house had been struck by lightning, and his parents had suffocated on the smoke. Devastated by the bitter irony, he left the town and has disowned his first name, only going by Blitz, and prefers to not talk about his Cutie Mark. He doesn’t blame himself, but hates the irony of it all. 2 months after the accident, he’s begun growing his previously short mane and tail out, and has bought a small house (with what little inheritance he had) in Ponyville, unable to go back to his hometown after what happened, generally keeping to himself whenever possible.