Clues

The following month after Victor left for his supposed adventure, he came to a certain settlement where the inhabitants there behaved less civilized, or in better terms, not as technologically civilized as the rest of the world. They didn't even seem to know that the world was different.

Victor, of course, did a bit of research, and what he found was definitely worth calling shocking, not that he was.

There was a certain cave close to this settlement, and the moment Victor got close to the cave, he received a system message that something was interfering with the system's functionalities, and also something was blocking the usage of his skills.

This discovery was certainly interesting. Victor went back to the village had to get more information as to what the cave was.

The villagers themselves didn't know what it was, all they knew was that it was a no go area for anybody, and were even shocked to see Victor return alive.