This is a very simple technique that doesn't cost hardly any chakra to do, but the user must also be a sensory type ninja. The user manifest a flame on the tips of their finger(s), then they find and lock-on to the chakra signature(s) they want to target and simply throw or shoot the flame from their tip. The guided flame moves at a high rate of speed and doesn't disperse when it hits objects that aren't the target, the flame simply goes through the object in the way unless its water or too hard to go through. Once it hits the target it disperses around their whole body burning them, this technique usually doesn't kill but can given the right circumstances.
