Chapter ten: Derpy Hooves.
Derpy was a person with a mental disorder but in the mutation her eyes ended up not aligning properly. She has her moments where she isn't that bright but she can actually be pretty smart at times. She has been surrounded by lots of people because of her disorder so she is very caring and whenever she visited a doctor that she regularly visited when in her human form her and her mother would always get a muffin after. Her memories of her love for the muffins carried through into her pony form. She didn't have many friends in her human form but the friends she did have she cared for deeply with the feelings mutual.
Dinky was actually Derpy's daughter that she had after a horny male took advantage of Derpy's disorder to have a one night stand.
Doctor Whooves is actually the best friend, though based off the Doctor Who for the fandom, that helped Derpy through her human life. His parents were actually doctors and he sometimes would get lessons from them. He liked to work on clocks though and wanted to be what he called a clock doctor.
Derpy did develop a crush on the Doctor because he was always there for her.
When the explosion happened the two of them got separated but became reunited and began working once again on their friendship.