No one actually exactly knows about the true origin of Ninjutsu. There are several stories and folklores. Some say that Ninjutsu was taught to humans by a creature half human, half crow or goat like. Others relate similar stories. It is an art more than thousand years old to which very few written records exist; most of the art is transmitted orally. Then several things are lost and added through every transmission. Thus it's difficult to sail exactly over the true history of Ninja and Ninjutsu. The only way is to discover from whatever record exists. For this purpose, I will relate from several shinobi traditions here: