The supporting character's harem is very normal - Chapter 238 Amleth, Doran, and Dorothy

A tale about the former leader of a special organization served under royalty, now leaving his past life behind and unintentionally getting involved with the martial world.

- Description from Novelupdates

Seventeen-year-old Hajime Nagumo is your average, everyday otaku. However, his simple life of pulling all-nighters and sleeping in school is suddenly turned upside down when he, along with the rest of his class, is summoned to a fantasy world!

They’re treated like heroes and tasked with the duty of saving the human race from utter extinction.

But what should have been any otaku’s wet dream quickly turns into Hajime’s nightmare? While the rest of his class are blessed with godlike powers, Hajime’s job, Synergist, only has a single transmutation skill. Ridiculed and bullied by his classmates for being weak, he soon finds himself in despair.

Will he be able to survive in this dangerous world of monsters and demons with only a glorified blacksmith’s level of strength?

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.

An unknown disciple from a small sect battling against the strongest in the cultivation world! The long journey working at cultivation, the realization of destiny and the chance to reach the apex of the world.