Douluo's signature is invincible

Introduction: Tang Ningchuan traveled through time and became Tang San's younger brother, and got a system that made him invincible by signing in. Then... "Ding, the check-in location is: Xiao Wu's bedroom, and the host is requested to go there as soon as possible." Dog Bi System, Sister Xiao Wu , that is my sister-in-law, I, Tang Ningchuan, am an upright gentleman, how could I do such a thing, I won’t go, I will never go.But... [Ding, check-in is successful, you have obtained the three ancient martial spirits of Douluo Continent, Devouring Spirits! ] [Ding, the check-in is successful, you get the God King Experience Card! ] [Ding, the check-in is successful, you get the Emperor Yan reward! ] ...This book is also called: Douluo's Devouring Fight...