The Regressed Demon Lord is Kind - Chapter 1

«Ding! You’ve received the [Human Archer (Stage 2)] and has activated the 10,000x bonus. You have received the [Flame God Archer (Stage 10)].»

A series of short stories in the world of Toaru Majutsu no Index organized into chapters featuring Kanzaki Kaori as the protagonist, going around the world and space doing missions for the Church of Necessary Evil, however, there is more than meets the eye as each incident is connected.

One chapter was bundled with each limited edition release of the Toaru Kagaku no Railgun anime DVD and BDs, with all of them together being equivalent to a single normal Toaru Majutsu no Index volume

On the day he experienced the most shocking betrayal of his life, as if that wasn't enough, he was beaten half-dead—and that was when the Infinite Wealth System awakened within him.[System Activation Complete!][Congratulations, Jayden Cole. You have been chosen as the Host of the Infinite Wealth System.][Now let’s fix your miserable life!]Thus, the Infinite Wealth System changed his life.The system tasked him with completing many challenging missions—some that could even threaten his life or land him in grave trouble—but the rewards were mighty![Task #002: Buy the most expensive item in a luxury store. Pay in cash. Say, ‘Keep the change.’][Reward: 1 Million Dollars!]---[Task #004: Slap your troublesome landlord with a rent receipt and say, ‘I just bought your building.’][Reward: 5 Million Dollars!]-------[Task #005: Take a beautiful rich lady you never knew to a 5-star hotel and spend one week with her. You must nut her twice or more!][Reward: 20 Million Dollars!]---[Task #007: Attend a luxury auction. Outbid a billionaire on a Rolex and walk away without collecting it.][Reward: 15 Million Dollars!]---As the world’s most dangerous and outrageous missions begin piling up—from dismantling corporations to outwitting billionaires’ most important workers and daughters—one thing becomes clear:Jayden won’t just climb the ladder of success. He’ll set fire to it and build his own throne at the top.Power. Vengeance. Wealth. Women.And one man bold enough to claim them all.

Luo Feng was reborn back in his high school years. From the start, he acquired the Return On Investment System.

[Invest in this coffee shop and you will be able to open many branches in the future. It has an ROI of 100%.]

[Invest in Bitcoins and the price will skyrocket in the future. It has an ROI of 10,000%.]

[Invest in the cute girl who is the deskmate in class and she will become your wife in the future. It has an ROI of infinity.]

Luo Feng decisively chose to invest in his future wife.

…

Many years later, during a press conference, a reporter asked, “Mr. Luo, your White River Investment Company has surpassed Morgan Stanley and Goldman Sachs, becoming the most famous investment management company. In your opinion, what is the most successful investment you have made in your life?”

Luo Feng looked at his wife fondly as he replied, “Don’t ask me. I just live off my wife.”