Ultra: Big Monster System

Kuroba was on his way to attend Ishiguro's fan meeting in Shanghai, but unexpectedly died in a car accident on the way. However, he is a lucky man. He became a member of the army of time-travelers! Let's see how Kuroba uses the "Big Monster System" to enter the Ultra World! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.