Immol'thar

Immol'thar is an ancient Voidterror, imprisoned in Dire Maul.

After the destruction of the Well of Eternity many Highborne slipped into lethargy. So it came pass that Prince Tortheldrin ordered to build up pylons. Those pylons created a force field that could imprison the mighty demon Immol'thar. Hungry for magic, the Shen'dralar quickly mastered siphoning the demonic energy from Immol'thar. That energy is used to grant these elves immortality.

Centuries later, the powers wasted to imprison Immol'thar and to control the pylons. So Prince Tortheldrin decided to kill some Shen'dralar to maintain his source of unlimited power.