With veteran K-pop songwriters, top-tier producers, and a perfectly crafted finale, the 'K-pop Demon Hunters' soundtrack is a surprise chart-topper.

A great K-pop song surprises you. It doesn’t whisper its intentions; it shouts them in multiple languages with a dance break in the middle. And in Netflix’s K-pop Demon Hunters, those songs also have to tell a story.

Set in a supernatural world where idols double as …