Well most people don't know her backstory so here you go :T
Thousands of years ago, when discord ruled Equestria, he created oddball- for company.
She inherited his power to cause chaos.. And a very odd colour scheme.
Hence her name. When discord was turned to stone, she ran to the everfree, out of fear of being turned to stone.
She lived there and only kept her power to herself. When she leaves the everfree, she sticks to the shadows and doesn't let anypony see her.
She is still scared of ponies seeing her. She has an albino, dwarf crocodile called Marshmallow :)
She lives in a house she built herself, a small wooden hut that descends under