What is your idea of Dark concept?

Eerie/scary aesthetics, optionally the song dealing with a feeling like anxiety or fear (of something actually scary), music that sounds like that (so not bright nor simply confident)

Dark seems to be broad for heavier music with dark clothes plus sexiness and/or fierceness. It exists within the mind in concept to bright which is bright clothes, aegyo, and poppier tunes. It's Run Devil Run vs. Oh essentially.