Illberd and Teledji are more interesting than Goth Melia Antiqua or anime Tensai-kun for the simple fact they're not deity-like or supernatural characters and still manage to cause damage in the setting that still lasts or lasted for years in the story the player is active at. Teledji went down quickly but he went very far for how much of an ordinary clown he is. Just to name a few, him and Illberd are directly and indirectly responsible for Thancred losing control of aether, Y'shtola's blindness, Shinryu and Omega's awakening, destroying the Crystal Braves and changing Alphinaud and the Scion's PoV of Eorzean city-states since, and to a lesser extent seemingly canonically made the WoL avoid drinking for like 10 years worth of cutscenes.