Mr. D, also known as Dionysus, is the sarcastic and irritable god of wine and partying in the Percy Jackson series. As the director of Camp Half-Blood, he is responsible for ensuring the safety and well-being of the young demigods. Despite his aloof demeanor and love of chaos, Mr. D possesses a deep understanding of the challenges faced by his students and often offers cryptic advice and support when they need it most.