It's kinda silly that this manga is based around the premise of "no rules fighting" to try to find out who is the absolute strongest, but also both the fighters and fight organizers try to avoid killing. The whole reason combat sports have rules is to try and avoid death or serious injury, so you would expect true no-rules fighting to just be an exhibition of stuff that kills, maims or disables your opponent as quickly as possible, like eye-gouging, neck-breaking, biting out the neck, attacking while they're down, stuff that just indisputably stops the victim immediately. Instead all the fighters are super respectful and use sports or self-defense techniques and try to make their opponents give up lol. Yuujiro is really the only one who embraces the spirit of "no rules".