The Singing Mountain Clan was a Dathomiri Witch clan village located near the Singing Mountain on Dathomir and a bitter rival of the Nightsister clan. Its leader was Augwynne Djo. Gethzerion used to be part of this clan before she was exiled.
The Witches of Dathomir (also referred to as either Dathomirians or Dathomiri) were a group of Human Force-sensitives native to the planet Dathomir. They were also known as the Daughters of Allya in honor of the wayward Jedi Knight Allya, who was banished to the planet around 600 BBY, and who they regarded as their ancestress. By the time of the Galactic Empire, Allya's descendants had divided into female-dominated clans that were named after regional landmarks. Each clan had a unique set of rules regarding Force usage, but all the clans held one rule above all others: "Never concede to evil".
"While rancors dined on others, the daughters of Allya prospered from generation to generation, teaching their own daughters the spells. We divided into clans, and for a long time the clans vied for men in friendly competition, stealing mates. We governed ourselves, punished anyone caught using the night spells. In my grandmother's day, we pushed the wild rancors from these mountains. My grandmothers hunted the last of them. We hoped for peace at last." - Teneniel Djo to Luke Skywalker
The counterparts of the Nightsisters, the Singing Mountain Clan has chosen a more peaceful existence on Dathomir. Although strong in the Force and despite overtures from the Jedi, few of the witches ever leave Dathomir, instead preferring a more peaceful existence with the clan. The Singing Mountain Clan draws on "magicks" as well, using them to tame rancors, heal the sick and wounded, and glimpse the future.