I’m the Slit-Eyed Character at the Academy, but I’m not the Mastermind Novel

The story starts with the MC playing a game that is “Very Difficult”, so difficult, in fact, that no one has ever managed to kill the last boss. After 18 years of playing and, having the best attempt be at 30% of the last boss’s HP, he decides to try out a character that he never used. This character was the Slit-Eyed character. It had garbage stats and garbage traits. But, since the MC had ran out of options with every other character, he was trying to see if he could find any secrets with this new character. So he puts in his name ‘Zero’ and presses play… Only to find himself inside the game, as the Slit-Eyed character.