Valkyrie's Shadow - Chapter 26Birthright: Act 5,

Su Wan is a Realm Destroyer. She shuttles to different time-spaces using the identity of the “Cannon Fodder Ex-Girlfriend”, dedicated to plotting how to happily tear apart the male protagonist and the female protagonist. –There’s no such thing as protagonists who can’t be torn apart, only Ex-Girlfriends who don’t work hard enough~

- Description from Novelupdates

One rule: Survive. Everything else is optional.Reika Kagetsu doesn’t want to be a hero. She just wants to feel—pain, fear, adrenaline—anything to remind her she’s still alive.Tenshiko Academy promised her that.What she got instead? Brutal training. No rest. No second chances. And monsters—inside and out.Now she’s fighting the Shikiban: creatures born from blood, madness, and buried secrets. But the deeper she goes, the more she begins to wonder...What if she’s one of them?Power always comes with a price. And Reika is about to pay it in full.

Being given a chance and reincarnated is nice and all, yet why do I have to become that male friend who just watches the protagonist flirting with his harem?---World: Kaguya-sama: Love Is War - Hyouka ----

Looking at the survivors, their faces the picture of despair, surrounded by zombies at the foot of the towering walls, Tang Ye stretched his arms wide and shouted: “Welcome to paradise!”