Time Travel: Starting from Having a Tsundere Sister

(Ten Cthulhu Foundations, ten no heroines, ten madnesses, and ten no systems) In ancient times, people discovered that various genes and bloodlines combined together could create different types of people with different abilities. From then on, the great era began to change, and various genetic species began to appear. The protagonist Li Feng rushed into the water to rescue someone when he encountered someone drowning. However, he was unable to save the person, but due to lack of physical strength, he fell asleep in the water and traveled to this world. After traveling to this world, Li Feng discovered that he had a sister that no one else could see. Many people say that Madman Li is sick, but is it the protagonist who is sick or the world that is sick?