The story of Aquaman involves his struggle to find his place in two different worlds. He faces challenges from both human and Atlantean enemies as he strives to unite the two and bring peace. His powers and connection to the ocean play a crucial role in his adventures.
Ryuuma Echizen was the male lead in the Japanese manga "The Prince of tennis" and its derivative works. Although he had won four consecutive championships in junior tennis in the United States, he was Japanese. After returning to China, he joined the Central Youth Academy, which was famous for tennis. Therefore, Ryuuma Echizen's nationality was Japanese.
In the original story of Aladdin, his nationality is often not explicitly defined. It's more focused on the magical and adventurous aspects of the tale.