11 parts Complete Mature(A Siren AU Story) (Billdip)
Dipper is a siren with such a beautiful and powerful voice, he attracts more than just humans ; ghosts, centaurs, fairies, and the like ; even at times angels and demons.
One day, his thoughts and dreams are invaded by a man who introduces himself as heir of the underworld.
His voice was so powerful, he attracted the infamous Bill Cipher.