Number Six from I Am Number Four is a girl that is also a legacy like Daniel (John Smith). Her abilities allow her to bend the elements to her will. Her Cepan has been dead for three years and she's had to survive on her own. This has made her pretty critical of John's inability to fight or think strategically. When Number Three died and she received the scar, she knew that she needed to try and find the others, so that together they can all make a stand against the Mogadorians.
