MTL - After I Was Reborn, I Devoted Myself To My Career - Chapter 4 figured out

Our straight (?) bottom woke up ten years into the future and found himself on the bed of his childhood friend… At the start, the bottom was shocked to his very bones, but he soon quickly accepted this premise and found the whole situation to be rather amusing. Precisely then, the bottom once again went back to his timeline — back to when he and the top were just platonic childhood friends.

One day, a tower appeared in the skies of all the major cities…

After an accidental death, in order to continue to live, Gu Bai had to choose to go through various wonderful books to complete tasks.

Every time he became a variety of small cannon fodder inside the story, Gu Bai’s code of conduct when completing task is – by all means, don’t be inferior, don’t be shameless, don’t be upright… hold on to a golden thigh.

… N times after transmigrating

Cannon fodder: (angry contempt) … You’re already so powerful, why are you still shamelessly holding on to a golden thigh to deal with us!?

Gu Bai: (deadpan) That… holding and holding… got used to it…

- Description from Novelupdates

“Kill Hamyuts Meseta”

A story about a world where all dead people become “Books” and are housed in a Library. The boy named Colio Tonies had his memories taken and a bomb transplanted in his chest. His life’s purpose is killing the world’s strongest Armed Librarian, Hamyuts Meseta. But, one day he gets his hands on the “Book” of a beautiful princess and falls in love at first sight. Furthermore, that love will cause Colio to get involved in a grand scale battle…