The protagonist of HXH, Jay Fulis, was swallowed by a monster when he was looking for something in the forest, so he traveled through time...
Then the boy was asked by his strange sister to become a manager, so he was locked by the game system...
To put it simply - Xiaojie travels through time and obtains a game system to experience the joy of tennis and all kinds of colorful and strange creatures in a world [deleted]chatting[/deleted] notes! OVER!
[Okay, I only think of this brief introduction at the moment...]
Version 2 (actually a backed up 233):
He was accidentally swallowed by a dimensional beast and got the system.
In order to go back and save people, I worked hard to complete the mission, but it turned out that the real purpose of the system was to kill Mary Sue, who had not yet appeared in Chapter 8.
However, when a colorful Mary Sue appears leading all kinds of strange followers...
Jie Fulix's mission is—ah, I'm sorry that the author won't reveal any spoilers.
The writing is a bit shabby, so please proceed with caution╭(╯3╰)╮