The Dark Crown

The Dark Crown (also known as MLP Project on deviantart) is a dark fanmade comic by Metal-Kitty.

Plot summary
Princess Celestia asks Twilight Sparkle and her friends to help unriddle a mysterious threat. When a dark secret of Celestia's past starts to surface, she decides to keep the Mane 6 out of it. Then one night, a dark creature comes to Ponyville and kill Twilight. Her friends later decides to do everything in their power to avenge her.

Starflare
Once a respectful unicorn professor of magic, and former student of Princess Celestia. He was introduced to Twilight Sparkle when she was a filly. One day, he had Twilight sit in a machine of his own design, made to release repressed magic and test it. Twilight's magic was so powerful, it caused an explosion in the lab. He saved her life, but at the cost of having half his face disfigured. He became traumatized when his wife, Locket, gave birth to a filly that died. A few months later, he was caught performing cruel experiments which resulted in countless deaths and was banished from Equestria. He created what is called "The Dark Crown", which Celestia broke in two and sealed away the halves. Years later, he returned to Equestria as a monster. He mutated himself with dragon's blood and scales of other various serpants.