At first, Prince Bo was snooty and a bit rude towards Hamtaro and his friends. But after Hamtaro saves him from Howdy's manic crowd of hamsters, he starts to loosen up. He is agile, cunning, and cares for his friends and the people of his kingdom.
At one point, he didn't like the fact that he was heir to the Rainbowland throne, but eventually accepted his position and took pride in his heritage.
Hamtaro was the first hamster Bo encountered while he was out of his kingdom. At first, he found Hamtaro too inquisitive and pushy, but realized that Hamtaro truly wanted to help him find the "most valuable thing". Their friendship is further strengthened when the Rainbow Queen's dragon illusion threatened to sweep Hamtaro and Bo away to their deaths. Bo holds onto Hamtaro tight, flapping his wings against the dragon's wing current. It is revealed by the Rainbow Queen at the end that Hamtaro and Bo's friendship was the most valuable thing.
The Rainbow Girls (Daisy, Ivy, and Rosy)
Daisy, Ivy, and Rosy are the loyal followers of Bo and they seem to be good friends, competing alongside each other in the Ham-Ham Games. However, Bo doesn't appreciate when the girls bicker with one another and even tests them in Thick Rainbow Girls so they can get along with each other better. He's aware that all three girls have a crush on him, but he doesn't seem to care much.
The Rainbow Queen
The Rainbow Queen is a mysterious, human-like, magical entity that rules over Rainbowland. She acts like a mother or mentor to Bo, and she understands his fears about becoming the king of the land. She creates a series of tests for Bo and Hamtaro to face and helps Bo realize that letting friends into his life might not be such a bad thing and to let go of his fears overruling the kingdom someday.
- Main article: Prince Bo/Gallery
- His English name is probably a play on the word "rainbow"; (Rainbow). His Japanese name is simply translated to "Rainbow-Ham".