Creatures of the Cthulhu Mythos and those who serve them are well known for using Eldrich song variants. Some others may have learned them as well, but Superiors of both sides discourage their use – the melodies they introduce to the Symphony make it easier for the Outer Gods to infiltrate reality.
These songs use Celestial Forces but also have a tendency to induce madness (in the form of Dissonance and Discord). As with all songs, knowing one variation increases the CD of all other variants by 1.