L'inferno nella mano

There are only three reasons to watch this movie. First, you were fooled into thinking Jackie Chan was the star. Nope. That's him sliding across the floor on his belly in the restaurant fight. Hi Jackie, good-bye Jackie. The second reasons are Chan Sing and Mars. Feel free to fast forward through all the other boring stuff until you see either of them. The third reason is the Mystery Man of Thailand. He shows up about 45 minutes in during a fight. He sits down briefly and does an excellent job of defending himself while seated. Then he gets up, I assume, to stretch his legs a bit or possibly to kick some butt. He displays excellent real fighting skills. I can tell from his posture he's the real deal. The fight ends and he is introduced as (depending on the translation) the greatest undefeated fighter in world history. Nice to meet you and sorry I must be going. That was it. So who was he? What else did he do? Is he Tony Jaa's father? Even Google does not know the answer.