Demon Lord

''This article is about the highest possible evolution of Monsters. For the Council of Demon Lords, see Octagram. For the Race of Spiritual Lifeforms, see Daemon''

Demon Lord (魔王) is a term used in two different fashions, either as a Monster class or as a social position. In general, it refers to the strongest or highest-ranking among Monsters, however, that is not an absolute rule for most definitions and there are various examples of beings who are not Monsters that are recognized as Demon Lords by societies.

Despite the foreboding name Demon Lord, not everyone who holds this title is of malicious intent, though the fact they are immensely powerful may be the root of such beliefs. Thus Lamrys and Milim's childish behavior and Rimuru's kindness and generosity often confuse those unfamiliar with their personalities.

High-level Majin
High-level Majin (上位魔人) at Hazard-class or Calamity-class, are not considered Demon Lords and they usually either serve as Lieutenants of Demon Lords or aim to become Demon Lords themselves one day.

Sub-Demon Lord Level (準魔王) refers to High-level Majin or beings of equivalent power on the lower end of Calamity-class. Individuals like Phobio and the other Beastketeers are considered as such.

Demon Lord-Level refers to individuals who have fulfilled the strength and Magicule requirement of a Demon Lord Seed, but might not have necessarily fulfilled the other conditions yet (obtaining a Demon Lord Seed, for example). They are usually ranked on the higher end of Calamity-class, possibly even reaching the lower end of Disaster-class.

Demon Lord Seed
Demon Lord Seed (魔王種) refers to those Monsters who have fulfilled the necessary conditions to be able to start the Harvest Festival. In terms of pure Magicules, they are at Demon Lord level, i.e. from high Calamity-class up to low Disaster-class, but usually a Demon Lord Seed has the advantage over a Demon Lord-level Majin, as the requirements for becoming a Demon Lord Seed are also useful in battle and would, therefore, tend to give the Demon Lord Seed an edge in such battle despite the magicule level being matched.

In some situations, the Voice of the World will announce the obtaining of a Demon Lord Seed and the individual will evolve to a higher species. For others, neither evolution nor announcement occurs, though they are still Demon Lord Seeds regardless.

The reason some Monsters go through this evolution when becoming a Demon Lord Seed is likely because their previous species could not handle the power of a Seed. For example, the Orc Lord was mentally disoriented due to the overwhelming power of his skill Starved until he became an Orc Disaster who could handle the burden. Rimuru likely didn't go through any evolution because Slimes are innately a race close to Spiritual Beings – on top of that, he possessed the nigh limitless capacity of his Stomach sub-space – thus he was capable of storing immense amounts of energy. It's unknown if those who go through an early evolution evolve again upon becoming True Demon Lords, or if they just gain the benefit of additional Skills and enhanced Magicule capacities.

Since Demon Lord Seeds are required to harvest human souls for the Harvest Festival, they require the ability to interact with and collect Souls of those they kill. It is unknown whether one of the conditions of becoming a Demon Lord Seed is being able to gather and/or interact with souls, or if becoming a Demon Lord Seed is what grants that ability.

Harvest Festival
The Harvest Festival (魔王ヘの進化) occurs once all the requirements to evolve are met by a Seed. The Voice of the World will announce it and the Festival will start immediately and cannot be stopped even by the one who triggered the event in the first place.

During the Harvest Festival, the one ascending undergoes a transformation in which they can physically and racially evolve and gain a tremendous amount of Magicules, though the exact amount may vary depending on the individual. In addition, the Demon Lord typically gains new or evolves existing Skills during the transformation. There is also the potential risk of a significant change in personality, usually towards more 'demonic' traits like callousness and cruelty.

Additionally, those connected to the ascended (via naming, Soul Corridors, or otherwise) will also receive "gifts" in the form of more Magicules, new and evolved Skills and potentially even further evolution.

True Demon Lord
True Demon Lord (真なる魔王) or Awakened Demon Lord (覚醒魔王) is one of the ultimate forms of existence that Monsters can attain, only below True Dragons.

According to the Voice of the World, the title Demon Lord always refers to True Demon Lords, while Demon Lord Seeds are clearly referred to by the Voice of the World as "Demon Lord Seeds". The only reason the term "True Demon Lord" even exists is to distinguish them from Demon Lord Seeds more clearly.

It is extremely difficult to fulfill all the conditions to reach this ultimate form of Monster-hood. Even those who have lived for many eons are not guaranteed such status, either because they couldn't properly increase their strength or Magicule capacity, or because they failed to fulfill the conditions for Demon Lord Seed and/or True Demon Lord.

True Demon Lords usually Range from higher Disaster-class to Catastrophe-class.

Notable True Demon Lords
Those who are known to be True Demon Lords by the time of Light Novel Volume 16: Game's End

Self-Proclaimed Demon Lord
Self-proclaimed Demon Lord (自称の魔王) refers to any individual that proclaims themselves as such. There are no restrictions to this and even non-monsters can claim to be Demon Lords. However, this usually has grave consequences depending on the individual's strength.

If the Lord in question is only at the level of a high-level Majin or even only at Hazard-class, one of the officially recognized Demon Lords will quickly destroy them by either sending their own subordinates to deal with it or attacking themselves, swiftly eliminating the self-proclaimed Demon Lord. Alternatively, the Lord might even die to armies or adventurers sent from the humans before the Demon Lords act.

However, if the individual in question is truly at Demon Lord-level (Seed or True Demon Lord), then they might be able to fend off or even kill the attacker. If that occurs, rather than being enraged at the newcomer, the other Demon Lords will instead usually view this as a display of strength and invite the newcomer to take the place of the attacker as an official Demon Lord.

There are no concrete examples of self-proclaimed Demon Lords that have been killed. However, two known Demon Lords became recognized through killing their attackers - Leon Cromwell, who killed Kazalim 200 years before Rimuru reincarnated, and Rimuru Tempest, who killed Clayman at the Walpurgis Banquet. In both cases, the Demon Lord Council recognized their strength, allowing them to use the title of Demon Lord and join said Council.

Regardless of the result, nobody remains a self-proclaimed Demon Lord for long.

Recognized Demon Lord
Recognized Demon Lord (認められの魔王) refers to self-proclaimed Demon Lords who have been officially recognized by the established Demon Lords. This can be achieved in two different ways:
 * 1) Getting nominated by other Demon Lords to join their ranks and receiving majority approval.
 * 2) Self-proclaiming to be a Demon Lord and then proving one's strength by defeating a recognized Lord.

Once a Demon Lord is recognized, that Lord also becomes a member of the Demon Lord Council and can vote on issues brought up by the council.

Demon Lord Council
Founded by Guy Crimson, the Demon Lord council is an organization containing all the recognized Demon Lords. The number of members and the name of the council has changed multiple times throughout the council's history, but at some point the maximum number of members was capped at ten and the name "Ten Great Demon Lords" was established. However, the organization was again restructured during a Walpurgis Banquet, and the resulting organization was labeled as Octagram by the "newbie" Rimuru Tempest due to only having eight members.

The only condition required to join the council is to become a recognized Demon Lord. Anyone who joins is automatically considered at least Disaster-class by humanity just for being a recognized member of the Demon Lord council, regardless of actual power. However, it's nigh impossible for anyone other than Lamrys to join the council without being at least at Demon Lord-level of power. After the restructuring, the Octagram has even higher standards since every member is already at least at the level of a True Demon Lord in power.

Trivia
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 * Prior to the creation of the Octagram, a large part of the world's populace thought the power of a True Demon Lord was equivalent to that of a Demon Lord Seed, as the most active Demon Lords - namely Carrion, Frey, Clayman, and Roy Valentin - only had Seeds, while the older True Demon Lords did not bother to show their true powers to the public for hundreds of years and instead preferred to act behind the scenes.
 * Demon Lord Seeds are implied to have the benefit of longevity, as Guy Crimson noted he had hopes Carrion would Awaken in 200 years.
 * The reason why only three Demon Lords are needed to initiate a Walpurgis Banquet is because the Council originally only had three people - Lamrys, Milim, and Guy. As the Council grew in size over the years, this rule did not change, thus leading to today's situation in the council.
 * The council also has a nonaggression pact between its members.
 * The Walpurgis Banquet is effectively a glorified tea party according to its members. However, because of the immense power and reputation of those attending, most of humanity views a Banquet as a bad omen for the future.
 * The Twelve Guardian Lords are Demon Lords themselves, but are not recognized as members of the council; instead, Rimuru gave them different Lord titles.
 * Benimaru's case revealed a caveat for the evolution to Demon Lord. He was from a royal family of a nearly extinct race; so he had to produce a few offspring in order to evolve. Demon Lords can reproduce.