Ki was used in the Martial Arts tournaments beforehand.
And with all the strange things that exist in the series that are already acknowledged by the rest of the world, such as the existence of Demon King Piccolo, talking pigs (Oolong) and other humanoid animals, guys who have a 3rd eye on their forehead (Tien Shinhan), and other weird things, why are their Ki attacks and flying abilities thought false just because Mr. Satan said they were?
And with all the strange things that exist in the series that are already acknowledged by the rest of the world, such as the existence of Demon King Piccolo, talking pigs (Oolong) and other humanoid animals, guys who have a 3rd eye on their forehead (Tien Shinhan), and other weird things, why are their Ki attacks and flying abilities thought false just because Mr. Satan said they were?