Koyuki is a character from the anime and manga series Beck: Mongolian Chop Squad. She is a talented singer and the love interest of the main character, Yukio "Koyuki" Tanaka. Koyuki plays a significant role in motivating Yukio to pursue his passion for music and join the band, Beck. In the series, Koyuki's character is depicted as supportive and encouraging, helping to develop the themes of friendship and ambition. Her presence in the story highlights the importance of following one's dreams and the impact of relationships on personal growth.