The main character is Kusuo Saiki, a high school student with extraordinary psychic powers. He can do things like teleport, read minds, and move objects with his mind.
Nendo could be a great addition. His simple - minded yet loyal nature can add some humor and unexpected twists. For example, he might accidentally almost expose Saiki's powers while trying to be helpful in a situation involving Teruhashi.
They might be quite surprised. Some characters could be amused to see the different interpretations of their personalities and relationships in the fanfiction. For example, if Nendo reads a fanfiction where he is depicted as a super genius in disguise, he would probably laugh at the absurdity of it. While Saiki himself might be a bit annoyed at some of the more outlandish scenarios written about him, like suddenly having a romantic relationship with a character he has no interest in in the original story.
There might be other characters like his classmates or friends who could be important in this 'little love story'. For example, a girl who might have a crush on Saiki and her actions and interactions with Saiki are crucial to the story. Her attempts to get closer to Saiki and Saiki's reactions form an important part of the narrative.
The Saiki K manga ended. It wrapped up the storylines and gave a satisfying conclusion to the readers. Although it's over, it still holds a special place in the hearts of fans.