One Piece: Fist of the World - Chapter 52: Gray Trapped in the Warship

When you get to the other world, you acquire new properties, there is no limit for your achievements and you become an overlord…Welcome to my world…

- Description from Novelupdates

Miguel transmigrated into the Wild Beast World in the body of a useless teen with the same name as himself after he was betrayed by his disciple, the Harem Emperor, for a knowledge and universal secret that he recently uncovered.In the Wild Beast World, humans could contract Wild Beasts through their Summoning Grimoire, a mysterious book that fated individuals can awaken at the age of 18.In this world of summons and beasts, Miguel awakened with the Beauty Sign-In System, which allowed him to contract legendary beauties as long as he signed in at a specific location.On his first sign-in, he received the Holy Daughter of the Red Family, the Fiery Empress of Legend.Using the Wild Beast World and the Sign-in System as a starting point, Miguel swore to return to the Immortal Cultivation World and settle scores with the Harem Emperor once and for all.Follow Miguel's journey as he reaches for the apex, becoming a legendary figure in all worlds.

Childhood sweethearts.
The most popular person in school is my childhood sweetheart.

- Description from Novelupdates

Earth’s top weapon specialist’s soul crossed over to an alternate world, merged with Rebirth Martial Emperor’s memories, cultivating Nine Dragons War Sovereign Technique, sweeping through all opposition with invincible might!

Able to refine medicine, capable of crafting weapons, and knows the art of inscription….

Being skilled in all professions is the way of kings!