Dreams/Ambition. A goal or a motivation of sorts to guide others and their beliefs. It can also drive someone to do good, evil, or whatever they think will get them in life, but there is also one more function from the core of an individual's dream. Sigils. Sigils are the magical ability surrounding the world, and they gauge how passionate you are about your ambitions of dreams. The greater the ambition, the stronger the power your ability.
Now the question remains, How strong do you think you'll be.