One day out of nowhere, high schooler Yuichi Sakaki begins seeing words above people's heads. It turns out to be the ability to see people's true natures, which he names Soul Reader! Actually, his big sister names it that. The next thing he knows, he's surrounded by people with bizarre labels like "Zombie" "Vampire" and "Witch. Fortunately, Yuichi is not unprepared.
My Big Sister Lives in a Fantasy World | Wiki | Light Novel Nation Amino
Nobody would ever believe him! Well, except for his older sister Mutsuko: This kind of stuff is right up her alley. Yuichi hasn't yet unraveled the secret behind his magical sight, but the end of his first school term is still as busy and can be! He's got survival club activities led by his big sister Mutsuko, early morning combat training with the serial killer Natsuki Takeuchi, and a first date with the vampire Aiko Noro with his little sister tagging along, for some reason.