The Master of Masters

The Master of Masters, also known simply as the Master, is a Keyblade Master who appears in Kingdom Hearts χ. Gifted with the power of foresight, he writes the Book of Prophecies and trains six apprentices: Ira, Aced, Invi, Gula, Ava, and Luxu.

Before Kingdom Hearts χ
During the "age of fairy tales", when the Master of Masters was a boy, the Keyblade War, a conflict between light and darkness began. This conflict continued for an unknown period of time, in which the Master saw many of his loved ones perish from darkness overtaking their hearts.. After the world is destroyed repeatedly, the Master crosses into a new Worldline, settling in Daybreak Town and composing the Book of Prophecies from events foreseen by his Gazing Eye. This allowed Darkness to peek inside the Book, but the Master intentionally remained vague in order to mislead his foe.

One day, Darkness asks the Master about his intentions for Daybreak Town, who reveals that his plans will result in the town's ultimate destruction. This declaration confused Darkness, as it doesn't understand why the Master would resort to plotting when he possesses the Book of Prophecies. The Master explains that the Book of Prophecies only depicts selected events and he intends to use it as his waypoint, while the Gazing Eye and Luxu's memories act his medium, giving him direct access to any destination in time. Furthermore, he intends to travel through time with seven lights on the Lifeboat. While Darkness admires the Master's cleverness, it refuses to reveal its own plans. In an attempt to get through to Darkness, the Master reveals that he'd seen a world which he cannot conceive, hoping to expand the world by rewriting the Book of Prophecies. When Darkness wonders which world the Master would disappear to, the Master teases that it is a world where neither light nor darkness can be controlled.

Enacting the first part of his plans, the Master provides each of his apprentices, excluding Luxu, with a copy of the Book of Prophecies, dubbing them "foretellers". The foretellers read through the Book of Prophecies and are horrified that the Keylade War will result in the expiration of light as the world reaches its end. The Master brings Luxu to the Control Room, wherein he reveals the truth of the Keyblade War and the existence of Darkness, as an entity, to his apprentice. He informs Luxu that he plots to have Ava gather wielders with a particular aversion to darkness travel to the world outside, where they'd gather light from the scattered worlds to rebuild the one destroyed by the Keyblade War, thus effectively calling a temporary truce between light and darkness.

Concerned, Luxu asks about these wielders, with the Master admitting that not all of them would be able to return to the real world. Luxu begins to doubt the Master, but as he had misunderstood, the Master explains that there is a way to defeat Darkness, however it is complex and will take several lifetimes to realize. Intrigued, Luxu asks if the Master had ever spoken to Darkness, and the Master admits that he had, though neither of them got through to the other due to their unconventional views - prompting Luxu to compare the two. Additionally, the Master reveals that Darkness is constantly observing them, but wouldn't approach them needlessly. As Luxu is still worried for the Dandelions, the Master allows him to watch over the Dandelions, so long as he dosen't interfere, as per his role.

The Master then bequeaths No Name to Luxu, providing him his role to continue on into the future with No Name, passing it down through a chain of apprentices in order to relay future events back to the Master via the Gazing Eye - though he'd do so without a copy of the Book of Prophecies in order to avoid temporal paradoxes. Additionally, Luxu would be taking the Black Box - though he is explicitly barred from opening it, though the Master does indulge Luxu's curiosity and tell him what lies within. When Luxu doesn't understand the reason, the Master explains that when the Lifeboat departs the world will end and those left behind will sink into slumber. Elaborating, the Master states that Darkness has cast away its form in order to attack people's hearts, but in doing so, its will begins to fade. Coming clean, the Master admits that there are thirteen Darknesses, and that they could be destroyed once they attained physical form. This is why that he had raised his apprentices so that their hearts would be strong enough to lock away the seven strongest iterations of Darkness, while five of the remaining six would be locked within the Union leaders, leaving the last to be caged within Data-Daybreak Town. Luxu is unable to accept their roles as sacrifices, follows his own path, ultimately becoming the Traitor.

Sometime after, the Master meets with Ira on the hill, providing him his role to succeed him as leader of the Foretellers in the event of his disappearance. While Ira resolves to gather as many Keyblade wielders as possible into Union, to maintain the balance of power in an effort to avert the Keyblade War, the Master claims that the war is inevitable.

After Luxu leaves to fulfill his role, the Master assigns the rest of the Foretellers with their own individual roles: Invi is tasked to observe her fellow Foretellers and act as a mediator; Aced is to become Ira's right-hand man when Ira takes over as leader; Gula is assigned to discern the identity of the traitor mentioned in the Lost Page and stop them; and Ava is instructed to avoid the imminent battles in favor of gathering exceptional Keyblade wielders, regardless of their Unions, to be part of a separate faction called the Dandelions, who would venture to another world to ensure the survival of the light. The Master provides Ava with a list of five Keyblade wielders she must gather to succeed the Foretellers following the Keyblade War, with only one of them meant to receive a copy of the Book of Prophecies.

The Master soon introduced the Foretellers to his latest creation, the Chirithy. Though the Spirit Chirithy are meant to aid Keyblade wielders in their endeavors, the Master warns them that if a wielder falls to darkness, so will their Chirithy, causing them to transform into a Nightmare.

Without warning, the Master disappears from the world to wait for his plan to unfold. Ava and Gula actively seek him out, but they are unable to locate him.

Kingdom Hearts χ
One night, Chirithy shows a dream in which the Master of Masters is speaking to the other foretellers in the Foretellers' Chamber, though Nightmare Chirithy quickly puts a stop to this dream.

Between Kingdom Hearts χ and Kingdom Hearts Birth by Sleep
Many generations later, the Master makes contact with a young Xehanort in the Corridor of Darkness, gifting the boy with a black coat, and has him tour the worlds to broaden his horizons. Meeting in the Keyblade Graveyard, the Master is surprised by Xehanort's revelation to side with darkness to prevent the World from falling into chaos. Encouraging the youth to believe solely in what he sees and that he will one day be strong enough to not need the black coat, the Master attempts to leave.

However, Xehanort asks for his name, and when the Master gives it, Xehanort reacts with shock, realizing that he is a Lost Master. Departing, the Master recites, "May your heart be your guiding key."

Kingdom Hearts III
Xigbar assisted Xehanort in kindling the Keyblade War as part of his plans to convene the foretellers, followed by the Master of Masters.

After the defeat of Master Xehanort, in Quadratum, on the roof of a skyscraper, the Master of Masters observes the spherical moon, and compares it to Kingdom Hearts.

Design
The Master of Masters wears a black coat, which obscures his features. His Gazing Eye, embedded in the No Name Keyblade, is blue with a vertical, slit-shaped pupil.

Personality
Although highly revered for his immense intelligence and foresight, the Master of Masters behaves in an unpredictable and eccentric manner, making his true intentions difficult to discern. He is a mischievous and playful individual, appearing curious about what will become of the world after the Keyblade War, in spite of already knowing the answer. Although he demonstrates a more serious side to his persona, especially when talking about the specific roles he had given to the foretellers, he has a tendency to weave in and out of serious moments at a mere whim, being somber at one moment and laughing playfully the next.

He shares a close relationship with his disciples, having inculcated an unquestioning loyalty to him within them, and treats them affectionately, though his eccentricity often baffles them. In spite of this, he manipulates them into starting the Keyblade War, without any apparent qualms.

One definite trait of the Master is his belief that the "truth" lies in what is seen and not spoken. Additionally and according to Luxu, though the Master is hard to decipher, one thing is clear: his absolute hatred of darkness, having formed all of his plans and actions around cultivating those that could trap and eventually defeat the darkness once and for all. He also claims to be afraid of facing the darkness without his black coat, indicating that his long battle against his enemy, and seeing so many loved ones and comrades perish due to darkness, instilled within him a considerable amount of fear to confront it without some form of protection.

Within his long discussions with Luxu, the Master mentions that the war that they are involved in is so grave, that they cannot let emotions interfere with the greater good of destroying the 13 darknesses and ensuring that people and the world, in general, can survive. This indicates that the Master's mischievous personality is an attempt to keep his emotions at bay as he enacts what he deems is necessary, namely manipulating his own apprentices, in order to ensure the survival of light and the defeat of darkness.

Abilities
The Master of Masters can spawn Keyblades from the hearts of others. He is highly intelligent, as he is able to create new entities such as the Chirithy Dream Eaters, and he is able to see the future with his Gazing Eye. Additionally, he has shown the ability to freely manipulate the Keyblades of other Keyblade wielders, as demonstrated when he summoned Xehanort's Starlight Keyblade into his hand. He is also able to cross over to the other world.