Jagged Germany - Chapter 4: unreasonable request

I, the protagonist, was just an ordinary NEET, but suddenly I was reincarnated as a tiny white snake in a fantasy world where legendary creatures and gods exist. Not only that, but I awakened in a cave as the offspring of a terrifying Medusa Serpent.Armed with only my human knowledge and my indomitable mental strength, I'm forced to use cunning tactics and rapidly evolving skills to survive against far stronger monsters and humans... So begins the survival story of a former shut-in with incredible willpower, living as one of the lowest-ranked beasts in a world of magic!ᆖMusic suddenly started playing in my head.I'd been waiting for this moment for so long.'Snakes! Assemble'....

Sa Bina was on her way to write her SAT when she suddenly finds herself in a strange world. She is sent to be the old emperor’s concubine, but on their wedding night, the emperor gets murdered by no one other than his own son and the heir! To survive, Bina makes a deal with beautiful but deadly Lucretius and her life in this dangerous kingdom begins.

The tale of Oliver.
An orphan boy from a Mine, in 19th century Europe, filled with Magic.

Mu Jingzhe transmigrates into a book filled with sweet, doting love to become the useless supporting character who serves as a foil to the female lead. She also becomes the stepmom of five kids to her recently deceased husband.