What Does the Second Dimension Mean?

What does it mean that after I traveled through time, the world barrier disappeared and the second dimension came over? Bai Ye discovered that since he turned eighteen, something inexplicable would always appear in his home every day. Sometimes it's a small tube of blue potion. I heard that once the tube is taken, all mankind will unite and fight against the outside world. Sometimes I am alone. The blond is good at medical treatment and likes to gamble. I drink wine occasionally and get benefits, but I have a bad temper. Sometimes it's a weapon, always trying to control him to destroy the world. But later Bai Ye discovered that not only his own home, but also the whole world seemed to have undergone different changes... [World Invasion includes games + animation + movies, new and old shows, Chinese comics, American comics, and Japanese comics suitable for Hong Kong movies, game characters, props and equipment]