Journey to the West: Sun Wukong's Advice System - Chapter 856 - 521: The Strange Era

Three Days of Happiness is a novel by Sugaru Miaki, also known as Fafoo. It’s a rewritten version of the story originally posted to 2ch.

The premise of the story revolves around a shop where one can sell away the remaining years of their life, and the consequences of doing so.

“I Say A Little Prayer” is a short related story which was posted along with the novel’s release. It spoils some things about the main story, but nothing major.

Xu Ke, the live-in son-in-law who had always been humiliated in the Lin Family, suffered countless indignities in this prestigious household.But who would have known that he was actually the heir of a top-tier wealthy family in the capital? When he inherits the family business, those who once scorned him can only look up to him.

An ordinary student, a wretched peeper, a cowardly teenager with a kind heart. In a terrorist attack, he inherited the knowledge of countless elites, embarked on a path of God Jagged Tu…

He is an artist!

He is a mathematician!

He is a psychology Doctor!

He is a master of fighting!

In fact, he is a man

Taken off raw site:

A wretched, dirty young man is working during the summer when he was caught up in a mysterious explosion. After that explosion, the young man is then left with the memories and knowledge of dozens of the world’s experts.

He has changed, his heart has become cold, iron-blooded. He became a killing machine, his mind turned mechanical, calculative. Everything goes according to his plans and calculations!

In this magical, slaughterous world, a door is opened for him…

- Description from Novelupdates

Traveling through the world of Naruto, he is just a four-year-old boy who has no talent, no family, no blood, and no tailed beast.

Unexpectedly, after completing the Jain test, the system suddenly awakened.

Since then, he has drawn the glittering fruit, the shaking fruit, the dragon-killing magic crystal of fire, the magic eye of death, Geass, the blood of the ancestor giant, the eye of reincarnation, the eternal kaleidoscope writing wheel eye…

Also, Demon Sword Muramasa, Death Note, Longinus Spear, Godzilla, Zanpakutō*Kyoka Suizuki, Zanpakutō*River Blade, Natural Teeth…

- Description from novelbuddy