Former Mamono Lord

The former Demon Lord is the monster that held the post before the current, succubus incumbent. For all the uncountable ages of the world except the current one, the Demon Lords have been grotesque, bloodthirsty horrors commanding hordes of gibbering, flesh-eating monstrosities, and this officeholder was no different. Historical events during their reign included the defeat of the pharaohs and the breaking of their desert kingdoms, as well as the war between Poseidon and the Demons of chaos. Aside from this, information on the former Demon Lord is very sketchy; neither its species nor gender is known. Even its ultimate fate isn't specified, although the usual fate of Demon Lords is to be slain by human heroes sent by the Chief God, and it seems probable that this is what happened to the former Demon Lord.

"Demon Lord" isn't just a title given to the strongest monster; there is metaphysical baggage that comes with the job. The Demon Lord serves as a sort of nexus for the monsters and their demonic energy; "Fear and respect towards the Demon Lord is imprinted in [monsters'] instinct. All of the monsters are subordinate to the Demon Lord, and they know from birth that the Demon Lord's energy flows within them. In the age of the former Demon Lords, the Demon Lord ruled the monsters through terror and fear using its immense power". Wandering Scholar relays the monster's account that the former Demon Lord - and all its predecessors - were somehow being secretly manipulated by the Chief God. According to them, when the world was created by the original Chief God, the reason that Demon Lords were included in the grand design was to maintain the yin-yang balance between the number of humans and the number of monsters. When monsters grew too numerous, the Chief God would empower human heroes; but when the humans grew too numerous, the Chief God would manipulate the Demon Lord to lay waste to human civilization. Needless to say, Order dogma strongly refutes this as grotesque heresy, and maintains that the first Demon Lord and the monsters "emerged from the darkness" contrary to the gods' plan.

When a Demon Lord falls, what usually follows is a chaotic and bloody interregnum where the surviving monsters butcher each other in an effort to secure the title for themselves. Since this is the period of time where human civilization generally builds itself back up, the position of Demon Lord can presumably lie vacant for centuries or millennia. In a departure from the usual course of cyclic history, this isn't what happened after the former Demon Lord's destruction. Instead of civil war, the monsters united behind a succubus to quickly produce a new leader.