First of all, Card World was a real world.
The continent was real, the place was real, the items were real, and the players were real.
Secondly, Card World had game-like settings. Therefore, there were resurrection, exchange, and friend functions.
In short, Card World was like an Otherworld with special rules. If one accepted the game settings, it was essentially like living in a game world, or the world of immortal cultivation.
The players came from parallel worlds with similar backgrounds, such as Blue Star, Earth Star, Gaia, and The Third Planet, and so on.
For various reasons, when players died or disappeared in their present world, they appeared in Card World. There was no need to struggle for a living here, and everything was like playing a game. They could completely let go of themselves.
Zhou Nan had been in Card World for more than half a year. At first, he had been playing normally, but later, when he did a quest, he found clues to a special achievement. This could be a notification from an NPC, a quest prompt, or a scroll. Then, he started to make progress to complete this achievement. It took him 69 days to complete it.
Therefore, Zhou Nan had been playing the game normally for the initial four months. He became familiar with some novice issues and the early maps. To complete the special achievement, he sacrificed four months of time, and started over.
When the White Angel Larken killed Zhou Nan, it was a special sanction, where his account would be deleted. He would be forced to start again from the initial state. This was akin to starting the game all over again.