Congratulations, C.C. Has chosen you to be a Geass user!
But first you must accept her contract!
Things that C.C. offers in the contract :
-active geass users
"If you had the strength, you could live. This is our contract. In return for my gift of power, you must grant one of my wishes. If you enter this contract, you will live as a human, but also as one completely different."