Superman's speed in comics varies depending on the storyline and the writer. Generally, he can fly at supersonic speeds and even approach the speed of light in some cases. His speed is often used to save the day and overcome impossible odds.
Maybe he uses some new jutsu. For example, he could have developed a special chakra - based technique that allows him to manipulate the air currents around him, much like how some wind - style jutsu work. This would give him the lift he needs to fly.
Superman's death in comics is often a result of epic battles or selfless acts. For instance, he might face an opponent whose power is just too overwhelming, or he might give his life to prevent a major catastrophe.