[DBrow]

https://en.wikipedia.org/wiki/I_Have_No_Mouth,_and_I_Must_Scream

The story is set against the backdrop of World War III, where a sentient supercomputer named AM, born from the merging of the world’s major defense computers, eradicates humanity except for five individuals. These survivors—Benny, Gorrister, Nimdok, Ted, and Ellen—are kept alive by AM to endure endless torture as a form of revenge against its creators. The story unfolds through the eyes of Ted, the narrator, detailing their perpetual misery and quest for canned food in AM’s vast, underground complex, only to face further despair.

[Dahoser]

I read that as part of my get to know Harlan Ellison for more than City on the Edge of Forever (which he disavowed and is a whole nother huge story) and being a creative consultant for Babylon 5. It's a brutal story.