It's the End of the World, I'm Going to Give My Boss a Knife First

Please Read a Well-Written Suspenseful and Brain-Burning Novel About the Bloody Group, and It's Best to Finish It.

I want to watch content similar to "River of Territory". Similar to "The River", "The Strange House" and "The End of Ten Days". It doesn't matter if there is a CP or not (just don't have a harem), and the protagonist has IQ but not a jerk, and is kind but not a virgin. Moreover, the group portraits are well written and the supporting roles are also outstanding.