MTL - Our Mommy is the Best Investigator! - Chapter 24 equivalent exchange

A teenager who unexpectedly gets transported to the modern world from ‘the world of the immortals’ . He finds himself in the body of an ordinary guy. He wants to go back to his world and for that, he will have to practice to get stronger and investigate the reason why and how he crossed through to this world.

- Description from Novelupdates

In a dramatic reversal of fate, the commoner Ludwik ascended the throne and became king. Once crowned, he was immediately told that the most important work of the king is “to welcome the princess from the highest lineage on the continent as your bride”! But then, the beautiful bride who appeared muttered, “gross…” upon seeing his face. Just like that, the new queen began to wage a cold war against Ludwik. But the truth is, there lies a secret within the queen’s heart, and when Ludwik finds out about it, he ends up in a certain contract with her… The story of fantasy, harem (planned), and comedy begins here!!

Reborn and returning, he possesses medical skills, can practice immortality, has a slave who is the king of killers, and a maid who is the school beauty pursued by everyone. Even casually taking out a piece of trash can shock the world. His return has set this world ablaze.