Toaru Majutsu no Index: New Testament - Volume 15, Chapter 1: Confrontation, or New Days — Turn_a_New-Leaf.

In a galaxy ruled by warlords, guilds, and ancient tech cults, Kai Zareth is just another debt-ridden scavenger—until a legendary system descends upon him.“One Trader per 10,000 light years. One chance to rise.”Selected by the Cosmic Trade Nexus, Kai becomes the sole wielder of the Galactic Exchange System, a multidimensional platform that allows him to buy and sell across parallel worlds, forgotten realms, and alien civilizations.With only 12 hours to complete his first trade—or lose everything—Kai scrambles to make deals in a universe where information is power and one wrong barter could cost your life.From selling enchanted goblin toothbrushes in toxic slums to outwitting rival system users and forging alliances with forgotten races, Kai must build his empire item by item, realm by realm.But in a galaxy where traders kill for profit and system users are hunted like prey, being the Merchant Sovereign might be a bigger curse than a blessing.

In the current era, people are either normal or are with ‘special abilities’. Cases related to the latter are managed by the “National Anomaly Prevention and Control and Special Species Management Office”.
Qi Zheng Emperor Sheng Lingyuan was reawakened a thousand years later after he jumped off the fiery Red Lake. Xuan Ji, a newly transferred staff to the Reparations Division of the Deviant Control Office, finds himself having to clean up the mess of a revived tyrannical monarch. The two seemed to share something from the past, but unbeknownst to them, a big conspiracy is stirring right underneath their noses that could destroy the balance of the world.

- Description from Novelupdates

Zaiden Archman. He’s the main character in my novel called ‘Awakener’s Dead Harem’.

As an author, I love it when my main character suffers and is depressed.

He’s the main character that I took pride in. With my novel about to end, I pushed myself to write the last volume.

However, what I never expected was that it would be the end of me too. When I opened my eyes again, I had become Vincent Dihart, an Extra in my novel, who is only mentioned a few times in the novel.

I then found out a sad truth about my Main Character that I took pride in. He has changed.

He’s not the Main Character that I made. He’s a Reincarnator. Someone has replaced my Main Character. And that someone has read my novel.

I feel empty and betrayed.

As an Extra, I will not be able to save this world from danger.

Only the Main Character is the one who can save this world. But, he will also not be able to do it without being depressed.

So the answer is clear.

“I will make him suffer.”

This is my story about living as an Extra. And once in a while, messing with the Reincarnator to make him suffer.