Entering the Buddhist path does not mean being heartless. The Arhat who was not subjugated was a compassionate one, he chatted amiably with the Dragon Kings of the Four Seas, reminiscing about his experiences and insights gained from his years in Buddhism, persuading the Four Dragon Kings to convert to Buddhism as well.
By then, there would be five Dragon Arhats in Buddhism, making the Dragon clan dominant in Buddhism.
The Four Sea Dragon Kings were delighted to see their brother, they recalled their love-hate stories with the Island Master of Penglai Fairy Island. These stories were deeply moving, and they persuaded the Arhat who was not subjugated to leave Buddhism to become the fifth Dragon King.
At that time, they would be able to overpower the Island Master, with all the oceans of the Nine Provinces under the control of the Dragon clan.