Since ancient times the Dark Elves have been ruled by a Hierarch, a "head priest". But after the Hierarch had been locked up by the Humans 400 years ago, the day-to-day affairs of the Dark Elves are taken care of by four Tetrarchs ("tetra" means "four" and "archein" means "to rule"), an office that is at present held by the venerable elders Kaitar, Talloth, Thifiell and Vellior. Of course there is a certain competition for the top position between the four Tetrarchs, but in times of crisis they all follow Thifiell.
"May Shilen's power shade you from the harshness of the light!
On behalf of the Hierarch, who was sealed by those despicable servants of the light, I represent the senior council that governs the race of darkness. It was I, Tetrarch Thifiell -- chosen by Gran Kain, the father of shadow, and Shillen, the mother of the abyss -- who led our brothers out of their underground exile and recaptured the FOrest of Shadow from those moon-faced Elves of light! You, child of Chilen! What is it that you wish to know?"