Rahu

Rahu or Rahula, was the Fiend Ancestor:

The person who had instigated the first Dragon-Phoenix Tribulation was the Fiend Ancestor, Rahula. He had used the resentment of living beings to forcefully cultivate the Ten Thousand Spirit True Spirit. After the Dragon-Phoenix War ended and the Primordial World was destroyed, the Demon Ancestor, Rahula, suddenly revealed his ferocious claws and teeth. He wanted to destroy the Primordial World and trace back to the Great Dao to pursue the opportunity to attain the Dao. At that time, the Ancestor of the Dao Sect, who had been cultivating in secret and did not care about the affairs of the world, stood up and fought with Rahula. In the end, Rahula was killed in the Aparagodānīya Continent.