summoning gone wrong?

a nobody on the floor 1. the first human to clear floor 100 First few people who cleared floor 300. never died from 1floor to floor 499. But on floor 500, a special boss appears. ‏‏‎ ‎ and I died?.wait how? floor 0 = Earth, Earth is peaceful, calm, steady. until you have to do homework, go to school. Hello, I am the author, this a story that is divided into two or more parts. this picture is not mine