Coo Erhard commands the Black Gema Gema Corps, a notorious group fixated on kidnapping protagonist Dejiko for profit. Debuted in the *Di Gi Charat Christmas Special* before resurfacing in *Reiwa no Di Gi Charat*, his narrative thread weaves through both eras. A precocious academic achiever, he skipped grades to earn a medical license, with expertise spanning dentistry and veterinary care demonstrated through collaborations with fellow corps members.

His appearance features short dirty blonde hair, reddish-brown eyes, and a canine-like tail, paired with a whimsical dog-themed cap. He perpetually clutches a stuffed panda, a cherished memento linked to treasured memories. Though occasionally petulant when defying orders, he exudes a composed, adaptable presence in both leadership and interpersonal scenarios.

Childhood ties bind him to Piyoko, the corps’ leader, fostering a relaxed dynamic that softens the group’s hierarchy. This connection cements his role as a mediator between Piyoko’s grand schemes and the operational duties of subordinates like Rik and Ky. While primarily an antagonist, his medical acumen and subtle mentorship occasionally surface as he navigates supporting Piyoko’s objectives with pragmatic finesse.