In this story, the legendary "master will" use imagination to make it real in fantasy. (It is said that there really is such an organization.) Under the twists and turns of the plot, I just want to explain two points: 1. The fate of mankind is dominated by a few people. Even if there is no such organization as the Master Society, it seems that such a fact cannot be denied. 2. All kinds of viruses and the process of causing death are different, but taking human life is their only purpose. Some of these viruses have existed for a long time, some are mutations, and some have no idea where they came from. Their killing ability is getting stronger and stronger, and the people killed by them are becoming more and more powerful. many.Are they created by someone, or did they come suddenly from some corner of the universe?

Nobody knows! It is the simplest and most direct way to say that it was spread by the God of Plague. After all, the story is a story, if you have read it, it is fine.