Global Travel Begins with Attack on Titan

As soon as I woke up, the world changed drastically, and animations and movies disappeared. Everything starts from scratch, a new life, a new life. The college entrance examination has become different. Doors have appeared all over the world. People have discovered that there are different worlds behind the doors. At the same time, a voice called the system has appeared in their heads. Soon people brought out forces that did not belong to this world from behind the door, and the world experienced unprecedented changes. This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.