Interstellar Wandering Mercenary

Teachers who are idle on campus and looking at beautiful girls everywhere An interstellar wanderer who salvages interstellar debris and relics. Escape from the brutal, foul-smelling planet Tridi prison with a legion of murderous escapees. Under the attack of alien races, human beings are retreating steadily, but the mecha warriors can stand alone. Humanity's last hope... That is his true identity?