There it is, my key. Don't let it boggle your mind, I will explain it. Our lower nature is our inborn selfish or self centered instincts. Our upper nature is the inborn altruistic or help others, even sacrifice self for others, instincts. Natures ultimate goal is to preserve the species or life in general, so it is survival of the fittest group capable of carrying on life in general. It is not survival of the biggest bully, but survival of the group.
The upper nature is ran by Mr. Do. He is the upper part of the brain that runs our bodies. That is unless Dragon from the lower nature does not rush in from the survival mode. If we are in a dangerous situation the Survival mode is the instinct to save us. First we Freeze and assess the situation, next we will Flight or get out of harms way, if trapped we will Fight, lie, cheat, steal, or even kill to survive. If it is activated or let loose without real danger it can cause lots of unnecessary drama and pain to self and others. Dragon is aggressive and will try to take over. Remember Dragon is selfish.
A more involved explanation of the characters can be read in the psychotoons.blogspot.com by clicking on it in the side bar.