The Grateful King is a famous composer and singer, whose skills in composition and music was legendary to everyone in the Sound World. However, since he is contracted with Unicorn Virtual Music, Dagger is using him on his plans on making him compose the most powerful song that would make him ruler of the Sound World. Due to his evil ambitions, he decided to possess the Legendary Instrument, Strawberry Heart, to rescue Cyan after being brought to the Sound World while using it as a way to communicate with her and the others. Now serving as Cyan's instructor in Midi City, it gives her advice on how to defeat dark monsters. It's sometimes called "Mr. Berry" by Cyan, apparently due to its long name. At the later course of the series, the members of BRR now knows about his existence.
Voice Actor: Yoshino Hiroyuki
Wikipedia
