Monarch of Gluttony: System of Sin - Chapter 147: 147: The Quest

Su Xiao is a cold-blooded teenager who’s seeking vengeance for the death of his family, yet things ended up badly for him.

As he was taking his last breaths, he heard a voice calling him from dimensions, it was a strange system reaching him, asking him if he wanted to be saved, to be Reincarnated.

He just needed to accept a contract, Su Xiao didn’t have any choice but to do so, but he didn’t know what he signed up for!!

Traveling through worlds, doing extremely dangerous missions, collecting special items, leveling up, and even killing Protagonists…

But Su Xiao wasn’t any ordinary Contractor, Su Xiao was a Hunter!

The MC crosses over to: One Piece, Tokyo Ghoul, Naruto, Fullmetal Alchemist, Attack on Titans…

- Description from Novelupdates

In the tenth year after the new era, the world finally came to an end. Zhang Mu truefully waited for his death, but unexpectedly found that he had returned to ten years ago. With his memory about the future, he swore that he would change the calamitous history, saving the earth from being destroyed! Walking dead, zergs, evolvers, and various mutated animals… nothing can stop him! The first step is to retrieve his identity as an era merchant , then find all the treasures he can remember to enhance himself!

Earth Immortals are cultivated from a blessed land.

Heaven Immortals move to and from the divine mountains.

I have a stalk of plum blossom, and I shall plunder the Will of the Heavens with it!

- Description from Novelupdates

Only a pure maiden can have a privilege to make contract with a spirit.

In Areishia Acadamy, maidens from noble family were gathered there, giving them an elite education to become a spirit contractor. A boy Kamito, by accident he peeped on a girl, Clair, who was taking a bath, and he even made a contract with spirit that she wanted.

Kamito was actually an irregular male spirit contractor, which should not exist.