Tethlis the Slayer, also known to the Dark Elves as The Butcher and the Scourge of Life was a tough and uncompromising King elected to rule the High Elves after Caradryel died. Tethlis was a ruthless military commander who fought to put an end to the threat of Druchii invasions. Tethlis commanded that every city in Ulthuan was required to establish training grounds and recruit even more Elves into arms. A firm believer in numerical superiority, Tethlis fought a series of massive offensive campaigns through the Shadowlands, gradually whittling away at the Druchii's numbers. Finally, with a huge army, Tethlis besieged the recently restored city of Tor Anlec and when the city fell, he earned the eternal hatred of the Dark Elves (if it was possible for them to hate the High Elves any more) by ordering that every Druchii in the city be slain - regardless of age or gender. It is likely that Alith Anar was also involved in this slaughter.
Unrelenting, Tethlis gathered a mighty armada and smashed through the Dark Elf fleet guarding the Blighted Isle. Thousands of Asur stormed the beaches under heavy missile fire, and were met by a maddened Druchii army. Gradually, Tethlis gained a foothold on the island, and methodically slaughtered thousands upon thousands of Druchii warriors, until even his own generals sickened of the slaughter. When the battle was over, Tethlis made a pilgrimage to the Altar of Khaine before he intended to join his navy, which was already pushing on to Naggaroth. At the Altar, Tethlis was cut down - although no one knows how. Some speculate that a Druchii assassin lay in wait for him at the Altar; others, that his own bodyguard, sick of death, struck him down when he sought to draw the Sword of Khaine.