Origin of Santa Claus?

I have been researching this for many years,and have found an origin of this story,in parts of Russia,Slovakia, etc.a person Ded Moroz,or people as it would turn out to be,were sadistic killers,who prayed mainly on children, whom they would take and sacrifice to their god(still researching this defunct religion).Ded Moroz naet b ropoa(santa claus is coming to town)used to be a phrase that would inspire the villages to hide their children.Ded Moroz only seems to have appeared around late December.So it appears this character we lie to our children about, used to kill them.