Dan Persimmon is a PhD candidate of Rinjoh University in the field of pokemon ecology, focusing on habitat stratification of common flying-type pokemon. He is in his late twenties, has curly light-brown hair, and is incredibly pessimistic about ever getting his thesis completed after seven years of working for Professor Spruce. Originally very thrilled about his field and academia in general, years of his supervisor changing goals, forgetting to sign papers, overlooking emails and generally causing Dan to miss deadlines and act as a clerk and general go-fer has caused the student to become very embittered with his career path.

When Spruce decided to move to Mango Village, he did not want to leave his valuble Relic Ball in the care of his colleague, but also did not want to put it into either the mail or the fast-transfer system. As such, he ordered Dan to carry it by hand, on foot, from Lemon City to Mango Village. Seeing this as the absolute low point of his career, Dan decided to take a four-week unannounced leave of absence by the time he made it to Tangerine Town, letting the slack fall to his coworker Marcie. When Matt, Seth and Jody were sent to retrieve the relic from Dan, they found him in the Sonic Boom Arcade; both the arcade's proprietor and the manager of the hotel he was staying at inferred that he had been spending a significant amount of time there.