Intro. The world is affected by the Tower of Babel. In the past, demons invaded and were sealed in the tower by the greatest mage at the cost of his life. Since then, the tower has become a cage of chaos and the source of power and interest. The terrain and laws in the tower are not fixed, and the higher you go, the more dangerous it becomes, but the more likely it is that artifacts, secret treasures, and magic essence will appear. Therefore, various races and cities have formed a traveler system. Travelers' guilds assign tasks, form teams, collect loot, and maintain the superficial balance of forces among all parties. Travelers are divided into seven levels from small to large: F, E, D, C, B, A, and S. However, the tower does not only affect the inside of the tower. When the tower's seal breathing intensifies, evil things will leak out at night, and abnormal strange tides will appear in city borders and remote areas. Elite monsters and small boss-level existences will seem to be pushed onto the stage by some force, forcing different forces to take action at the same time. So you will see the crusade teams of various major forces enter the same mission list, including sect forces, city-state armed forces, and consortium-affiliated brigades.