Kei Hiragino is a main character in the anime series Moetan. He is a high school student and childhood friend of Ink Nijihara, the protagonist. Often referred to as 'Ah-kun' by Ink, Kei is intelligent, gentle, and somewhat oblivious to Ink's feelings for him. Throughout the series, he plays the role of Ink's love interest and is often the source of her motivation to improve her English skills. Kei’s supportive yet unaware presence is central to Ink’s personal growth and the series' comedic and romantic moments.