MTL - Mermaid Effect - Chapter 3

When a fantasy kingdom needs heroes, they skip the high schoolers and summon hardened Delta Force operators.Lieutenant Cole Mercer and his team are no strangers to sacrifice. After all, what are four men compared to millions of lives saved from a nuclear disaster? But as they make their last stand against insurgents, they’re unexpectedly pulled into another world—one on the brink of a demonic incursion.Thrust into Tenria's realm of magic and steam engines, Cole discovers a power beyond anything he'd imagined: magic—a way to finally win without sacrifice, a power fantasy made real by ancient mana and perfected by modern science.But his new world might not be so different from the old one, and the stakes remain the same: there are people who depend on him more than ever; people he might not be able to save. Cole and his team are but men, facing unimaginable odds. Even so, they may yet prove history's truth: that, at their core, the greatest heroes are always just human.

Lyle Walt is a young noble boy and heir looking forward to the day he can inherit his family’s territory. Except around when he was 10 year old, his parents started neglecting him more and more in favour of his little sister, Celes.
On his fifteenth birthday, he is challenged to a duel by his sister to see who will inherit the household and horribly loses, being cast out of his family. Afterwards, he gets treated by the family groundskeepers and receives the family heirloom Gem from him that Lyle’s grandfather had entrusted to him. From there, he begins an aimless journey with his childhood friend and former fiancée, Novem, and the Gem-turned-Jewel that houses the memories, personalities, and Skills of seven of his ancestors.

In the 21st century, a female military doctor, Lu Jiao, transmigrated into a novel and became the vicious mother of four little villains and the wife of the future First Assistant.

In the novel, the four little ones would grow up into villains who committed all kinds of crimes and killed people without batting an eye. Eventually, they would end up getting killed by the male and female protagonists. To avenge his sons, the First Assistant would transform into the final boss and die after committing many sins.

Lu Jiao looked at the four little ones who were only up to her knees, then looked at the bedridden First Assistant. Forget it, she would do a good deed by educating these children properly and giving the First Assistant medical treatment while she was there.

What she didn’t expect was that the four little villains and the future First Assistant would want nothing more than to send her to her death.

They attempted to strangle her in the middle of the night, use broken pieces of porcelain to slice her arteries, and poison her food. Lu Jiao was furious. “I’m not doing this anymore. If you want to become villains, go ahead.”

However, the four little ones now refused to let her go.

“Mummy, please don’t go. We’ll be obedient from now on.”

When Linger was looking for a job, he applied for a bartender at a bar, but the guests who came here seemed strange.

What can a female warrior wearing very little, an armor that can’t even protect her eyesight, protect against?

How did the calamity mage who owed a hundred luck points survive until now?

Melancholic and lonely Skeletor, Skeleton? drink wine? Please don’t waste it!

The devil who likes the hero, since he is the devil, please do your job well, OK?

…

Well, he was getting used to these strange guests.

(Unknown Uncomfortable Sky: “Presenting Fine Wine for a Wonderful Different World”, “Sword and Magic and Beautiful Girls”, “Wine of Beautiful Girls”, “God-level Bartender of the Other World”, “I’m Really Not the God of Dionysus”)

- Description from novelbuddy