Although I personally consider Mal’Ganis a more popular dreadlord in the lore, Tichondrius is much more impactful in that he was involved with so much up until now. The leader of the Nathrezim Dreadlords, Tichondrius was a very prominent character in Warcraft III, yet never actually made an appearance in World of Warcraft (other than a level 48 flashback quest in Cataclysm, that you can find in Felwood). In the Lore, it was Tichondrius’s job to supervise the Lich King as he was preened to become the newest force of the legion on Azeroth. Upon Arthus’s fusion with Ner’zhul’s spirit, Tichondrius pretended to serve the Lich King s a vassal, while continuing the Legions invasion of Azeroth. Supervising the death of Uther Lightbringer, the destruction of the high-elven city of QuelThalas, and the eventual summoning of Archimonde; Tichondrius was eventually put in full control of the Scourge as the Legion believed that a Lich King was no longer needed. It was after this that Tichondrius used the Skull of Gul’dan to corrupt northern Ashenvale; creating what is now known as Felwood. What he didn’t expect was Illidan Stormrage, tipped off by Arthas, using the remaining latent powers in the skull to become a demon himself, allowing him to put an end to the dreadlord.