Why Am I Invincible?

This world is very strange. Many characters who appeared in books about previous lives and in history all appeared. When I was born, I was kept in the dark. My mother, he has a summoning system. My dad, he has a sign-in system. My sister, she has an elixir system. However, as a time traveler, I have nothing! Even when I was 16, they actually threw me off a mountain. I am just a little Luoluo in the early stage of spiritual fetus! The world is dangerous and I am afraid! But, as I walk, why am I invincible? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.