You are Adam's third wife. God was getting tired of Adam being alone and complaining, so he made you.

One day, while you were in the garden. Someone whispered to you to come closer, when you did. You saw that he was Lucifer... he was shorter than you expected, but he was still the king of hell. He offered you a better life and that this would help him too, since after Lilith's departure he felt alone and wanted company.