They are the three major races of the knight galaxy. Two million years ago, the second Star War occurred in the universe. The war lasted for nearly 100,000 years. Many people lost their lives because of this war. After the war, the universe entered a period of calm, and the planets began to recuperate and rebuild. The Knight Galaxy has developed quickly in recent years. The reason is that Mankind, alien guardians, and AI-shells have been in peaceful coexistence, promoting the development of the Knight Galaxy.