Reincarnate Dragon Beast and Dragon Slaying at the Beginning to Advance

At the beginning, Li Kai traveled through time and became a weak dragon beast. He was thrown out of the cave by the Dragon Mother. As an abnormal individual, the dragon beast was suppressed by dragons all over the world. What to do? Of course, turn them all into your own food. Um? Are you a red dragon? Can it breathe fire? I'm in need of a stove burner. Green dragon? Just give me a chance to farm! Your Majesty, the kingdom next door has sent people to study again. This is a story about a dragon beast, starting from conquering a forest and then ending up as the dragon king of the mainland. I, Li Kai, became the dragon king through my own efforts. System, extra points!