The Lab

In this story, Dr.Robotnik adopts the orphaned children that loose their parents thanks to his conquest to rule over Mobius. Everyone old enough to remember his deeds are robotized, but the youngest are who he raises in secret to teach them about his genius. Through this process, he ends up finding and raising Tails.

Tails immediately becomes the favorite, even if the Doctor won't admit it. He bonds with Tails through the love of technology and robotics and Tails ends up helping Robotnik with the development of a lot of the machines used in the outside world and in war. Of course, the children of the hidden facility don't know about about the war, or any of the bad things Dr. Robotnik had done. They are only taught about how much of a good guy he is. Sure, Robotnik's pushy/rude side shows through sometimes, but the children still love him. He's their father.

The children are held in a secret underground lab. It has a main dome filled with trees and nature to keep the kids healthy and enriched. They have chores to keep them busy and are taught by Robotnik and his nanny robots about the world. Of course the Doctor is extremely biased with the material. He says the world outside is dangerous, and that people are trying to kidnap and hurt the children. The Doctor paints himself as a hero and protector so that in the event Sonic and the freedom fighters ever manage to find this place, the children would resist.