In , the song " Butter-Fly " serves as more than just a nostalgic theme; it is the emotional and thematic backbone of the series' finale . Originally the debut single of the late Koji Wada in 1999, the song has become the definitive anthem of the franchise, representing the "immortal butterfly" spirit of its singer and the journey of the DigiDestined. Thematic Significance of "Butter-Fly"
The film uses the butterfly motif to explore the bittersweet reality of growing up and the inevitable "metamorphosis" from childhood to adulthood. Digimon Adventure : Last Evolution Kizuna - Butterfly