Coo Erhard  

Major, クウ＝エハルト

Coo is thirteen years old and serves as the leader of the Black Gema Gema Gang. He also acts as their physician. Being Piokos childhood friend, he holds a special place in her heart and is considered her closest companion. On occasion, when food flies through the air, Coo exhibits a dog-like behavior by jumping up to catch it with his mouth. Although the gang views themselves as a family unit, Piyoko believes she is older than him despite being only eight years old while he is thirteen.