The journey begins with a little statement in harp and flute over the Studio Ghibli logo. As the narrator tells us about the old forests and gods, a short little hint of the Forest Chords is given, played with con sordino violins. When we see trees in an ominous old forest, a quick independent motif played by the mandolin and other supporting instruments, plays. But as soon as we see a shadow lurking behind a tree and ripping it down, the mood changes and trumpets play quick bits of the Demon Theme. Finally, we can see the demon destroying vegetation and the full Demon Theme plays for the first time in low woodwind and brass.
When the title card is seen, Ashitakas Theme plays in violins and flutes, hinting at the journey that's about to begin. But as we see Ashitaka observing his surroundings, his theme is reharmonized (A#m - Dm), hinting at the danger that's about to come. As he hops back on Yakul (his giant serow) the Iron Town/Eboshi Chords (A#m - G#m6) play, hinting at who's responsible for the demon that's about to confront Ashitaka. As the rider speaks with Kaya and the other girls and later rides to the watchtower, the Demon Theme slowly builds up with high violins and xylophone (later supported by trumpets). Ashitaka getting off Yakul and climbing up the tower is supported by the melody of his theme, played with xylophone, harp and flutes, but with the Iron Town/Eboshi Chords (A#m - G#m6) underneath. As he starres into the forest only contrabass played staccato and anvil hits (again further making the connection between Iron Town/Eboshi and the Demon) create tension. Ashitaka climbs further up and we hear a full statement of the Demon Theme played staccato. As Ji-san and Ashitaka discuss the situation a little hybrid of Ashitakas Theme and the Demon Theme is heard. Additionally, a short phrase of the Village Theme sneaks in as Ashitaka mentions it.
As Ashitaka draws his bow against the unknown danger, we hear just the anvil hits without the contrabass staccato. Flutes play the beginning phrase of the Ashitaka Theme. We can see more and more of what lurks in the forest and the quick trumpet runs of the Demon Theme return. Shortly after, the full theme bursts out with the whole brass section playing it as we can see the demon slowly crawling towards the tower. But as it's revealed that the demon is possessing a boar, the Boar Tribe Theme is heard in a contrabass ostinato. The Demon Theme continues in a triplet figure played by staccato trumpets. As Ashitaka warns Yakul to run away, we hear a small statement of Ashitakas Theme played with flutes. But it's greatly overshadowed by the Demon Theme as the demon destroys the watch tower. A final statement of Ashitakas Theme plays as he and Ji-san must jump from the tower with a single tubular bell hit ending the cue.