Light's Sister (Lawliet x OC)

Kiki Yagami is Light Yagami's adopted sister. While they aren't flesh and blood they are as close as twins would be. Kiki is as smart as, if not smarter, than Light. Light is highly protective of her, because she is often picked on a bullied. Light sees her as his innocent 'little' sister (they are the same age) when in reality she is far from innocent.