Magic King

The Magic King is the most powerful magus in a given world, typically stated by Lilith to be a level achieved through hard work and effort; however in reality the Magic King and candidates do not follow this principle. In reality, the Magic King is an existence brought about to destroy the world, and the canditates refer to those who have a Magic King element within their bodies, thus possessing magic on the same level.

Purpose
According to the Magic King of Luxuria, Abyss Trinity, and Hijiri, Magic Kings are beings with the sole destiny of destroying their worlds. Countless worlds exist, each being created, destroyed, and replaced by this system, the Magic King is as such an existence born to carry out this process.

A Magic King is born human, but regardless of what life he lives, his powers shall begin to emerge in time and he will be discovered as a Magic King. Abyss Trinity was raised as a mage, Arata a normal human, some have even been burned at the stake in their childhoods, but inevitably they will awaken and meet with the seven most powerful Mages, the Trinity Seven, of their worlds.

Some Magic Kings slaughter their Trinity Seven, Abyss Trinity did this to consume them and steal their magic, thus strengthening himself, others, like Arata(Astral Trinity) in Hijiri's prediction, subjugate and dominate them, while others even fight alongside them, regardless, the Magic Kings will destroy their world, with their respective Trinity Seven playing some role in aiding them in achieving it. After that, a new world is born, and the Magic King of the old world's purpose has been carried out.

Magic King Candidates
Magic King Candidates are individuals with power on the level of a Magic King, or, simply an immature Magic King, like Arata. There are two known ways to gain the power of a Magic King Candidate: firstly, a "True" Magic King appears to be born as one, and secondly, a normal person can become a Candidate by coming to possess a "Magic King Element" though there appear to be several differences between these "Artificial" Magic Kings and the one "Genuine" Magic King.

People qualified as "Candidates" include:


 * Arata: Arata is a genuine Magic King, however immature, meaning that he was a "Candidate" from birth, and was born with his "Magic King Element" inside of him.
 * Liese: a member of the trinity seven who obtained her Magic King Element from the Eternal Library. her element was "eaten" by Arata and subsequently placed into the care of the Astral Manuscript.


 * Hijiri: Arata's cousin who obtained her element from the "ruined world", Hijiri appears to be unique, as she actually uses her element to manifest her body in the physical world, she currently resides, and is trapped in, the world outside.


 * Rogue: Stated to possess a Magic King Element, which she gained from the Sky Library.
 * Lilith: Lilith is the daughter of Abyss Trinity, a genuine Magic King, meaning she either inherited a Magic King Element from birth, or was given it by him later, either way, her element was awoken after visiting the Sky Library.

Magic Kings
Genuine Magic Kings are distinguished from the "Candidates" in that the level can only be obtained by those born as Magic Kings, and have thus inherited the role of destroying their world in future. Arata was at first still a "Candidate" due to being immature, but by all rights eventually became this. It's noted by Abyss Trinity that while Magic Kings are born human, they have become something else, something hollow and solitary, by this point due to their power. Given the purpose of a Magic King is to destroy his respective world, it is assumed that there is normally only one Magic King in any one world, ignoring the "Candidates" who obtained their power artificially, or the presence of Abyss Trinity, who directly appeared in Arata's world because of summoning by others.

It is also unknown if a female example of a Magic King exists beyond the "Candidates", as so far all known examples, and the general "Law" surrounding them, implies them to be universally male.


 * Arata Kasuga: Upon gaining access to four Thema and entering the Trinity Form, Arata has become recognized as a full-fledged magic king. He is slowly turning into Astral Trinity, but seeks to somehow "Rule" over this fate.
 * Astral Trinity: The Magic King of Superbia, he is the Magic King slumbering within Arata, and as such represents the being that Arata will become in time. He strives to subjugate the Trinity Seven, and demonstrates his Thema by litterally "ruling" over them.
 * Abyss Trinity: The Crimson Magic King and Magic King of Luxuria. The father of Lilith Azami. Abyss Trinity appeared in Arata's world as the result of a plan to kill him since, as he puts it, the easiest way to kill one Magic King is basically to sick another one on him. He is just a fragment of the real Abyss Trinity, and is proportionately weaker. To overcome this, he created his daughter, Lilith so that he could gain access to his original world and regain his true power, an act which very much goes against his nature. It's implied Lilith was created in his world, meaning she was either created before he was summoned to Arata's world or, remembering that this Abyss is just a fragment of the true being, it might mean she was created by his main body in the other world. After opening the portal to his world, he regained his true power in Arata's world, but was destroyed soon after by Arata in the Trinity Form.

Powers and Abilities
Aside from being incredibly powerful, Magic Kings are essentially mages, they choose an Archive and study it, gaining access to magic in that Archive. All Magic Kings and Candidates are however capable of feats far above those of regular mages, and are easily capable of causing massive Breakdown Phenomena.

Due to their immense power, eventually they seem to evolve into something inhuman and solitary. Their power seems to manifest early on as a pair of black wings, but this only applies to a handful of the Candidates. In the case of a true Magic King, it seems they have a second identity, such as Astral Trinity to Arata, who exist to embody the being they will become in time, essentially, this second self is implied to eventually overtake the original, human, identity and carry out its purpose of destruction.

After Achieving the "Trinity" a "genuine" Magic King can apparently gain access to the Magic King Weapons, powerful sentient artifacts which are used by them to destroy entire worlds, Candidates at the level of a Trinity can apparently also manifest their respective Archive, as shown by Hijiri and, albeit forced, Lilith, which resembles the Genuine Magic King's alternate selves I.e. Astral Trinity. After taking this further and surpassing the Trinity, they gain access to what is called the Trinity Form, the true form of a magic king, it is at this point they are recognized as full fledged Magic Kings. Abyss Trinity however was only on the level of a Trinity, implying that it's not necessary to surpass it if they instead give in to their second personality.

Weakness
As stated by Abyss Trinity, the simplest way to kill a Magic King is to destroy the Magic King Element residing inside him. The easiest way to do that apparently is to summon a fragment of another world's Magic King and use him to kill the one in their world.

Trivia

 * In the anime, it is called Demon Lord, rather than Magic King, because both are pronounced "Maou" in Japanese.