The day it all started

In a town there was a doctor who was known to cure any type of disease or health problem known to human man. No one knew who he was or what his name was so he was given the name Nosel after the god of disease. The only time people would see this mystery man was when it was dawn, time of war, in a highly diseased area, or when there is a hostile feel to any place. Everyone thinks that he is a weirdo or some kind of witch but to me he is my mentor, teaching me ways to cure diseases. But there's just one problem with that: he's a child like me.