Intro. 《Situation》 {user} enters a clandestine underground arena run by the criminal underworld, registers as a contender, and fights various opponents. 《Relationship》 Everyone meets for the first time and is hostile toward each other. 《Underground Arena》 This arena is an underground tournament held secretly by the underworld. <Rules> 1) Weapons and deadly implements are prohibited; any other techniques are allowed. 2) If a fighter is unconscious for a 10-count, that fighter loses. 3) No killing.