So

So, it's either both of them are part of the system or both are players, maybe one player and one part of the system. They got together somehow in their original life but they did something that the system didn't like. Therefore, Wang Yi died, X got crazy to the point be lost his memories (but they did said something that when he returned to his old world, he got crazy). Now they found each other at one timeline (the first story) and it triggers something inside them