The Flame God of War in Douluo Continent

Being in another world, there is something wrong with this Douluo. What is it that Tang San's biological mother is Bibi Dong, Qian Renxue's biological mother is A Yin, and the Star Crown Sect and the Blue Lightning Overlord Sect are the twin sects protecting the country of the Star Luo Empire. What does it mean that there are barbarians, Di tribes, Rong tribes, and Yi tribes outside the mainland? Poseidon Island was beaten and retreated to the mainland.