After submitting to Dawu, Zhu Shan took Chu Yuan to White Cloud, East Shang, and hundreds of islands nearby.
The overall strengths of these three major islands are roughly equal. However, White Cloud Island is a bit stronger, with more than 300 million inhabitants, while East Shang Island has only over 100 million. After all, these are just islands in the sea, not true continents, and can't accommodate such a large population.
Upon Chu Yuan's arrival, the people of White Cloud and East Shang were naturally unwilling to submit to him.
However, Chu Yuan directly set up the divine enormous cannon, blew several uninhabited deserted islands flat in front of them, and showed them the head of the chief of Tiger Shark Island.