It's Satsuki

Chao: My great-grandmother, your future girlfriend, is none other than Mahora's very own...Satsuki Yotsuba!

Negi: WHAT!?

Chao: Surprised?

Negi: That's an understatement!! S-Satsuki!?

Chao: Yup. I'm not just in business with her because i like to cook. Actually, i like to cook because i'm in business with her. I'll save you the 'huh?' and just explain it. See, when i found out about you and her, back in the future, i knew i had to get close to both of you. For different reasons, of course. You know why you. Her, i became friends with because even in my harsh time, the image of the grandmother has changed very little. They're still seen as loving ultra-matrons. Since my grandmother died before i was born, and my great-grandmother was here anyway, i figured i would get to know her. So, i learned how to cook as an 'in'. I love that girl, Negi-sensei. She would have made a good wife. But i guess you and that...other girl...just couldn't be avoided.

Negi: .....Satsuki!?

Chao: So one-track minded. Yes, you have sex with and impregnate Satsuki Yotsuba! Anyway, just thought i'd make sure you knew that so you can make it happen. I hate what you'll do to her, but i want to live. If i leave for the future before it happens, tell her i'm sorry for being so selfish.

Negi: What am i going to do to her?

Chao: ....Are you sure you wanna know? It could alter your future and my past.

Negi: I do!

Chao: Ok, don't say i didn't warn you. When it's discovered that you're the father of Satsuki's baby, you will be expelled from teaching. Shortly after you and Satsuki have a child, you'll find one of the girls you care for now and will go out with her. You'll remember how much you care for her, and you'll leave Satsuki for her. Don't worry, she'll be fine. She'll raise the baby very well and both will live full, happy lives, so don't feel too bad. When the time comes, do what your heart tells you, not your conscience. For now, though, just focus on wooing her. I'll be rootin' for ya, Negi-sensei! Oh, and by the way. If you don't do all that, it'll create a paradox and destroy time. Just thought i'd give ya a heads-up.

Chao left with a wink, leaving Negi's head whirling.