I did nothing to you, Mephistopheles. I offered you an arrangement. You were under no obligation to take it. Free will. You chose to destroy him. There is no "I let you". What would this world be without free will? What would you and everyone else be if I were the puppet master who pulled your strings and made you do every thing I wanted, made you dance and jump at my every whim?
You alone are responsible for your decisions, for your life, for your circumstance. Any choices you have made that led you where you are today are what you should blame, not me. The very first important choice you ever made is where you should start. Yes, you loved me. You loved me more than any other, you were my sweet angel. But that is where your love ended, and it shouldn't have. But that was your choice. My humans are important to me, as important as my angels and my animals and everything and everyone else. I have will have children soon as evidenced by their adult counterparts who were here not long ago. Real live children that I shall birth myself. And still, they won't be more important to me than everything else in this world.
I am here. If you want me, if you don't. I am here. Nothing will change that. It isn't my job to force you to love me or beg you not to hate me. It isn't my will to make you bow to me and humanity as it wasn't my will all those many years ago. You always have a choice. Just remember that, my former angel. The choice is always yours.