Sun and Moon were created in a laboratory they were made to create full life to take care of children... But the scientists would treat sun and moon so horribly that they even got scars on their body. The caretakers didn't care for them as much or as you could say the scientists they were just experimented on all the time, And mistreated it got to a point where Moon became super defensive of sun. And some became sad and fragile but he was happy and cheerful around children.