Ojarumaru, or Prince Mackaroo, is a manga series and an anime series created by Rin Inumaru. In 2006, McDonald's Japan ran a toy series based on the characters.
There appears to be 3 different toy sets, (Pictured Below) one including keychain toys and two without. The First, smaller 6-toy set being produced in 2006. The year the second and third sets were produced is unknown.