[@Zelosse] I have an idea for a pair of twins.  Each born with one of the elements of light and darkness. While similar in appearance, the are both unique. The brother, lighthearted and fun loving, wields darkness and acts more like a guard to his sister when she's feeling overwhelmed. She is more shy and withdrawn, more oft to make mistakes. 

I wanted to see what you'd say before filling out sheets for them.