Making up a Diary to Save the World

A system came to a boy while he was sleeping at home, asking him to use the special characteristics of a realistic diary to save the dilapidated world in the future. At first, he just wanted to be invincible? But somehow he changed his mind. In this group portrait, humans all over the world work together to save humanity. The protagonist is relatively selfish at first, and every character in it has some shortcomings. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.