Cousins are (obviously) the Prince's cousins. Since Katamari Damacy, the series has introduced more and more cousins. In conventional canon Katamari games, the grand total is 58. (57 excluding The Prince)
During We ♥ Katamari, the players could see the life of the King of All Cosmos from childhood to adulthood, however, the cutscenes never portrayed, or even hinted, that the King had brothers and sisters, neither that the Former King had other offsprings. This may imply that, either the Queen of All Cosmos had siblings that gave birth to most (if not, all) of the cousins, or that maybe the King has other family members that the games didn't acknowledge yet.
Katamari Damacy - Cousins
Katamari Damacy had 23 cousins, 24 including the Prince.
- The Prince
We Love Katamari - Second CousinsEdit
We Love Katamari added 16 cousins. These are called second cousins. The original cousins, in one way or another changed their looks and features in this title as well (such as Velvet having artificial legs and Jungle becoming transparent)
Me & My Katamari - RookiesEdit
Me & My Katamari added 8 cousins.
Beautiful Katamari - Half CousinsEdit
Beautiful Katamari added 8 cousins These are called half cousins. (Note: The Princess is not really a princess.)
Katamari Forever - ???Edit
Katamari Forever added only 2 cousins. Namco-Bandai did not mention what these 2 new cousins would be called. The newest cousins also have different names in Japanese.
Katamari Damacy Online, a Korean game by Windysoft released their own set of cousins. This game isn't available outside of Korea. The more commonly known cousins outside of Korea are Mint, Mellow, and Wink.