| Kingdoms will burn!
This article contains spoilers relating to World of Warcraft: Legion! If you wish to avoid potential spoilers, please be cautious.
Kil'jaeden, also known as "the Deceiver," was a demon lord and one of the former eredar leaders on Argus alongside Velen and Archimonde before Sargeras arrived and brought the eredar into his cause, the Burning Legion, save for Velen, who escaped with many others who became known as the draenei. Meanwhile, Archimonde and Kil'jaeden continued to serve the Burning Legion as Sargeras' right and left hands.
The Deceiver was summoned by Kael'thas Sunstrider at the Sunwell Plateu at the time of the Burning Crusade, but while being summoned he was pushed back by adventurers of Azeroth. Kil'jaeden later imbued Gul'dan from an alternate universe Draenor with his vast knowledge before sending him to Azeroth to pave the way for the Burning Legion's next invasion. The invasion was eventually pushed back by the forces of Azeroth, and an angry Kil'jaeden, defying Sargeras, launced an attack on Dalaran. After the Armies of Legionfall assaulted the Broken Shore, Kil'jaeden fought them within the Tomb of Sargeras.
Kil'jaeden will serve as the final boss of the Tomb of Sargeras raid.