The Mask Man And His Four Disciplines

For all of Denver's whole existence, he wanted to be in normal life. He doesn't like to engage in any trouble. He only loves to do is to sleep when he has a chance and never mind about problems that were coming to his life and the school he was working at as a janitor. But the truth was when a problem came to him, he will instantly find a solution to this, and never give up. Until one day, a huge explosion in the school happened that made some of the students, teachers, and even Denver can't survive. They died without saying goodbye to their loved ones. But not Denver. He doesn't even have a family. He's an orphan, a young man who lives his life on the street and does his best to survive in a cruel society. When Denver opened his eyes, he can't believe what he saw. He's in his own body, but he's no longer in his world. He can't even utter a word when he found out that he was summoned by a famous demon in Renzocka World who was also one of his comrades when someone summoned him to another world 3 decades ago. But how could that person become a part of Renzocka World? 'What happened after I choose Earth over that world? Why they're here all of a sudden?' That's all Denver's thinking after meeting his four disciples. And he decided to unleash all the secrets just to get information on what happened back then. And who was the mastermind of all the chaos?