truly scary japanese horror novels

Sam unexpectedly acquired a dating simulation game named "The Female leads Truly Loves You". He was quickly captivated by the game, which featured numerous beautiful female leads. Crucially, it was a harem-style game where the mc could maintain romantic relationships with various female leads and engage in sexual relations with them. Just when Sam thought achieving sexual relationships with these female leads was the game's goal, the ending shocked him profoundly. When all the female leads discovered the male protagonist's love for multiple girls, they exhibited inexplicably insane behavior. True to the game's title, "The Female Leads Truly Loves You", each one wanted to possess the male lead exclusively. The crazed female leads resorted to extreme measures, killing the male protagonist. They dismembered his body and preserved it in formalin. They decapitated him and kept his head by their pillows to accompany them in sleep forever. They drained his blood to create a specimen, ensuring they could see their beloved male lead every morning. ... Realizing his fate would be death, Sam chose to avoid these female leads. However, they seemed to possess magical abilities, always finding him using various means. Fortunately, Sam had a system. By thoroughly conquering these female leads, he could avoid the deadly ending and even gain enhanced abilities.