Isekai Maou to Shoukan Shoujo no Dorei Majutsu - Volume 10 Chapter 3 part3-4

There was a mysterious old man who approached the failed swordsman with the “100 million years button”. A magic button which can achieve the same effect as training for 100 million years if you push it.

The failed swordsman who pushed the button had his doubts, but immediately felt tremendous power rising in his body. So he pushed the button many times.

However it was a cursed button. The moment it was pushed, he was confined to the 100 million years prison of time. The first 100 years were devoted solely to training. After 1000 years he had forgotten why he swung his sword. He stopped thinking completely after 10,000 years had passed. After 100 million years he became crippled and finally managed to return to the real world. At the same time losing all his memories from the past 100 million years, the only thing that remained were his sword techniques. “I can become stronger just by pressing the button!” or so he thought and pushed the button many times after that. Foolishly trapping himself in that 100 million years of hell each time.

As he continued this loop, he began to think “If I destroy this world, will I get out of here?” A few billion years later, he finally escaped from the loop.

This is the story of a failed swordsman trying to make a name for himself in the world.

Different Hollywood, different life, there are only wonderful works, telling a new legend.

- Description from novelbuddy

I exist in the darkness, disappear under the bright light, and will eventually devour the sun and turn into the shadow of all things… Known by people as the indescribable terror of darkness; the king of shadows; the dark day; the existence of the shadow of the world , is still just a somewhat special high school student, facing a weird death game…

- Description from novelbuddy