My Fantasy Comes to One Billion Years Later

Novel Summary
Across the billion years, Lin Tian has become the guardian spirit of a beautiful woman one billion years later, and can freely travel between the two eras.
Antiquity is the rule of this era, and the more ancient the exercises are, the more powerful they will be after a billion years. Lin Tian, a billion years ago, said that this era is dominated by me!
– Description from soxs