The divine plan called for the angels to serve the humans on earth - guard them, drive the wind and rain for them, distribute provisions, etc. While Adam's body remained on earth, the real person, the soul, was admitted into Heaven in the outermost universe. God gave Adam certain commandments, represented by the forbidden tree, and Satan was appointed as Adam's companion to deliver to Adam his satanic message. The rest is history. Every time a human being is born, a human person is assigned to the new baby from the depository of souls.
Every soul deserves to be assigned to a certain body, and live under certain circumstances.
God alone knows which souls are good and which souls are evil. Our children are assigned to our homes in accordance with God's plan. An independent jinn soul is also assigned to the new human being to represent Satan's point of view. While the physical body of any jinn is reproduced from the parent jinns, the jinn soul is that of an independent individual. A continuous debate takes place in our heads between the human soul and the jinn soul until both of them are convinced of one point of view.