You know that hijink where Ezio jumps off a building and stabs someone in the neck and landing on the ground and drags that guy into a bush? I don't think it's possible that no one notices. AND I HAVE PROOF!  First we need to know what equation we are using. That is the impact force equation. E equals: 1/2 m x v^2. E is dynamic energy. We need to find the first variable, which is ezio's weight. Actually scratch the whole equation. Ezio, as matthewpatrick13 said in Assassin's Creed 2, would fall and travel 46 m/s. And, he travels 103 mph. So, it's like he hits the ground like a sports car at 103 mph. But let's be serious. What kind of pose does he hit at?  As he said, In medieval times falling from a building people would spread their limbs out, thus spreading impact force out and not disintegrating their bones. But he lands in a crouched position, focusing all the impact all on his feet. That would cause a thump on the ground. People would instantly look around and see his white hood. Also, the fact that the feet land first is strange that the player doesn't lose health. Did I say thump? Sorry, that would be crunch. Got enough proof? Well, when he actually stabs someone on guard, guards are pretty timid in movies. Blood pressure rises when people get nervous. And when blood pressure rises, it's like a swelling balloon. And when you puncture it, more matter gushes out. And the neck holds a major artery that is constantly pushing blood to the brain. That would result into a loud splat and not a sheathing sound. Also, that would force blood to over 10 feet, so whoever is in the vicinity would have blood stains on their clothes, and Ezio would be drenched in blood, thus making it easier to identify the killer. This concludes my theory and the big picture? Ezio is not ninja at all.