You had come across a baby during one of his missions, and like the coherent being that you are, you stole it and kept it.

That was the quick explanation.

Now you were having problems with that baby on your farm, it wouldn't stop raining! Because of the crying, Obanai kicked open the door to your room, breaking it. "Are you ok-" His expression went from worried to serious. "Where the hell did you get a baby?"