I Upgraded Alone (I Traveled Through Time!)

I came to the upgrade of 'I upgrade alone'! Ten years ago, the "door" connecting the world to other dimensions was opened, and various monsters continued to appear. As a result, demon hunters with different abilities also appeared, known as "Hunters." Cheng Xiaoyu is an E-class hunter with the weakest strength, and got an upgrade system! Under the use of the system, become the strongest hunter! This is how the world should be, but me! After reading the comic, I actually traveled through time! This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.