Ultraman Agul is the blue Ultra hero who appears alongside Ultraman Gaia in Tsuburaya Productions' late-1990s tokusatsu series Ultraman Gaia. His theme is part of the show's heroic orchestral soundtrack, written to underline Agul's serious, sea-linked power and his uneasy alliance with Gaia. As clips from the series spread through fan edits, reaction videos and soundboards, the short theme became a shorthand cue for a powerful entrance or turning point. It remains popular because that heroic brass melody is instantly recognisable to tokusatsu fans even in a clip lasting only a few seconds.