Yu Otosaka was not always an egoist and liar. The changes in his character began the moment he unexpectedly discovered a paranormal ability that allowed him to inhabit another person's body for exactly five seconds. Having acquired such a useful power, the young man did not marvel at it; instead, after stretching his mind a bit, he eventually found a suitable application for it. What would you think? In studying.
Sneakingly "kidnapping" the bodies of diligent top scorers, Yu repeatedly copied on exams. In the end he graduated from high school with honors and entered a prestigious upper‑secondary school. And then it was left to little things: slipping into the best university in the same way and thereby securing a prosperous future for himself and his younger sister.
Over time everyone around him seemed like idiots, which only reinforced the man's ambition, firmly confident in his uniqueness. A uniqueness that some once wanted to argue about… And then the cunning Nao Tomori, appearing as if out of nowhere in a literal sense, without much gloating, knocked the pride off the self‑satisfied trickster as soon as she said that people like him are not uncommon in this world.