The Split-Tail clan was major Nephilim clan whose territory at its peak ranged from Northeastern Exile through Eastern Gallery from before the founding of Avernum all the way through to the Empire-Avernum War. It was the most prominent clan in those parts and large enough to be considered real threat to the Kingdom of Avernum.
The centre of power for the clan was the Nephilim Castle and at its peak it was jointly ruled by Chief Charrar and the High Shaman Mrrrrmm, with the later inclusion of the human mage Zemera; making the leadership a triumvirate.
It is unknown when the Split-Tail clan first appeared in caverns. Officially the Nephilim were first came to the caves when the Empire began the mass exiling. However, the Split-Tail clan were around at the time of the First Visitation as the Nepharim offshoot of the clan were able to take the hilt of the broken Demonslayer back to their fort in the Eastern Gallery to be interred in the crypt of their leader.
Decades passed as the clan grew, until the first Avernites arrived in the caves. Due to other problems like the Demonlord Grah-Hoth the Split-Tail clan were ignored excepting minor skirmishes, at the same time smaller band and stray Nephilim were absorbed by the clan. From this time the clan began it's campaign of raids and banditry and started construction of the castle which was to be the seat of power.
In 817 IE the strength of clan began its descent with attacks and the deaths of leaders from several bases, including the slaying of the ruling triumvirate.