Everyone Thinks He is E-Rank But He Can Easily Defeat SS-Rank Demons 

It’s the year 2093 in futuristic Japan, where monsters of unknown origin appear out of nowhere and terrorized humanity. At the same time, global crime rates reached an all-time high amidst the chaos. Humans had no effective method of defeating the monsters, and governments worldwide got spread thin trying to deal with all problems.
Everyone Thinks He is E-Rank But He Can Easily Defeat SS-Rank Demons