Toaru Majutsu no Index - Volume 15, Epilogue: The Victory Prize for Those who Survived. Nano_Size_Data.

When Roland crossed Middle-earth with the Lord of the Rings system, Gandalf was organizing an expedition, the king under the mountain still did not return to his throne, the Hobbit’s adventure had not yet begun, and the world was still shrouded in shadows…

- Description from novelbuddy

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

Suzuki, an adult programmer, suddenly notices that he’s been thrown into a different world while wearing a casual clothes at level 1. He gained high levels and treasures after using the 3 times use-disposable-magic, Meteor Shower, once. After that he intends to do different world “sightseeing tours”? He meets 3 beast girls, beautiful purple and black haired sisters, and an eccentric blonde haired elf girl along with various people during his trip. Although there are occasional fighting with demons and demon lords, this is a heartwarming fantasy story at heart.

As the owner of an ordinary bookstore, Ling PingAn’s biggest wish was to muddle through life and do absolutely nothing.