I Transmigrated Into a Book and Became Cannon Fodder in the Apocalypse, and Now the Yandere Powerhouse Begs Me to Spare Him

[No female lead + post-apocalyptic zombies + male lead adored by everyone + not a self-sacrificing saint + powerful leads + complete ending] I... transmigrated into a book! And not just any book, but an unfinished post-apocalyptic novel with two male leads! I’m a good young man of the modern age, fresh out of university, and already facing workplace bullying, forced to sell my life for a paycheck! And after transmigrating into a book, I still got stuck with the fate of a cannon fodder! No! I don’t want to die again! There’s no way I’m giving up. If I can’t go back, I’ll just survive here. Rule number one for surviving after transmigrating into a book! Stick close to the protagonists to stay alive! There’s strength in numbers! But... the protagonist is so handsome, so manly. Yeah... I’m in love. Holy crap! Is this the other protagonist? So manly! The powerful-pair setup really is the best! Whatever, I’m right here, so I might as well ship them! But... wait! That guy’s eyes look kind of strange. No, hey! Dude! You two are the canon couple! What does that have to do with me, the cannon fodder?~ This is crazy, everyone’s gone crazy. I’m just a little cannon fodder trying to survive! Don’t go doing anything weird, hey! [Ice-cold, loyal, scheming top (the original top) A seemingly saintly but secretly sinister, unhinged bottom (the original bottom) A sweet, naive, naturally seductive bottom, adored by everyone, CP undecided. If that’s not your thing, move along.]