The Strongest DragonSlaying System

In a cultivation world where humans resides with dragons. But even if human beings becomes stronger, they will be suppressed by the dragons. The true ruler of this world is the Dragon! Ning Qi was a young mafia boss on the earth, but was betrayed by his most competent subordinate who pushed him down the cliff. When he woke up, he found himself located in the dragon's continent and became the 13th son of Champion Duke of Qin Tang empire. At the same time, the super dragon slaughtering system was also activated, which changed his fate. Who are Ning Qi’s biological parents? Where are they? On this continent, how is Ning Qi’s past-life identity amazing?