Crone Hellebron is the most Ancient Hag Queens save only Morathi for they where the first Brides of Khaine. But while the youth and beauty of Morathi can be renewed, that of Hellebron is now expended. The power of blood no longer refreshes this ancient Hagqueen as it once did. Each year more young elf sacrifices are needed to fill the cauldron' and yet the effects last less and lesstime. Morathi has keep some secrets of cauldron only for herself, so Hellbron must now endure many dark months as an old ugly crone for each day of renewed youth.
Hag Hellebron
As leader of the Cult of Khaine, Hellebron rules over the city of Har Ganeth. In addition to a horde of frenzied Witch Elves, Hellebron can call upon the deadly Executioners of the city and raise the populace to arms with promises of Khaine's favour and threats of his bloody displeasure. Now the Hagqueen prefers to cloister herself in the Temple of Khaine during her long months of decrepit suffering.
Source
Dark Elven armybook