Sergeant Pepper directs the "Aikatsu boot camp" on an uninhabited island, where aspiring Idols who have deficits in their performance, to be brought up to speed. The camp has a reputation for being incredibly hard and actually requires the Sergeant them at the beginning physically a lot from, but this was actually only the warm-up in the end. The accent of the instructor reveals he is from America. He also operates an idol training camp, participated in the Hoshimiya Ichigo during their one-year stay in the USA. He's still in good memory, because, in spite of the language barrier made it, to go along with everyone else in the camp of their courage and dedication.
His name is a play on Sgt. Pepper's Lonely Hearts Club Band, an album released by The Beatles