Darkness (character)

The thirteen original Darknesses are a group of characters introduced in Kingdom Hearts Union χ who possess a history with the Master of Masters.

Darkness is an ancient entity locked in an eternal battle with the light. While they originally possessed physical forms, they currently exist without a body, so instead seek out hearts to inhabit. Of the thirteen, one's whereabouts are unknown following the destruction of Daybreak Town, four are trapped inside Data-Daybreak Town, and the rest reside in the hearts of Ventus, the five Foretellers, Luxu, and the Master of Masters.

Before Kingdom Hearts Union χ
Long ago, Darkness possessed physical forms, but cast off these forms in their battle with the light, thus leaving thirteen Darknesses. In order to propagate and increase their numbers, they turned to attacking hearts, with people succumbing to their negative emotions and giving rise to the Pureblood Heartless.

When the Master of Masters was composing the Book of Prophecies with knowledge passed to him via the Gazing Eye, Darkness watched over his shoulder, reading the passages as they were entered. Because of this, Darkness learned that Ventus would harbor Darkness in the future. Darkness would also have conversations with the Master of Masters, but they were unable to understand each other's thoughts and positions. Even so, Darkness views the Master of Masters as an "old friend".

Following the Keyblade War, hearts of the Foretellers, Luxu, and the Master of the Masters became hosts for the strongest seven Darknesses, all according to the Master of Master's plan.

Kingdom Hearts Union χ
Right before the start of the Keyblade War, one Darkness takes Ventus as its vessel and strikes  down Strelitzia, stealing her Rulebook and giving Ventus her spot as a new Union leader. Darkness then disguises itself as Ava and instructs Ventus on his new role.

Another Darkness approaches Maleficent following her defeat. Darkness explains to her that she is trapped in a data world, part of the Master of Masters's plan to ensure that Maleficent would be unable to alter the past.

Darkness then guides Maleficent to Data-Daybreak Town and the lifeboat hidden within the clock tower. It reveals that the device will allow Maleficent to return to her own time, requiring only someone with memories of her and a medium to recreate her body in the future. Further, should Maleficent use the lifeboat, she will be able to serve as a waypoint to allow someone to travel into the future, Darkness explains.

Maleficent hesitates to return to her own time, which allows Lauriam to discover her presence. After revealing the function of the lifeboat, she battles the Union leader, winning with Darkness's help and returning to the future. Darkness, however, remains behind in the real Daybreak Town.

The Darkness lurking in Ventus's heart exposes itself to the Union leaders. Lauriam attacks, enraged at Darkness for killing his sister Strelitzia, but he is easily defeated in his weakened state. Brain questions Darkness before raising his Keyblade agaist it alongside Ephemer and Skuld.

With most of the Union leaders defeated, Darkness is coaxed by Brain into revealing its true plan: infection. Player arrives and the Keyblade wielders prepare to fight Darkness once more; their victory in the battle is short-lived, as Darkness is unable to be destroyed with no form. However, Ventus awakens and uses the light within him to dispell the creature of darkness.

Meanwhile, the Darkness that remained in the real Daybreak Town speaks with Luxu regarding Luxu and the Master of Masters's plans and the whereabouts of the remaining four Darknesses.

The four remaining Darknesses appear to Player, Ephemer, and Skuld in Data-Daybreak Town. The Darknesses want the Keyblade Wielders to open the gate to Game Central Station so that they can spread to more worlds, and Ephemer and Skuld prepare to battle the entities in response. However, Player appears to be posessed by Darkness and fights the pair of Union leaders. Defeated, Ephemer sends Player and the four Darknesses to Game Central Station, while locking the gate from his own side. In the conduit between the Data Daybreak Town and Game Central Station, Player reveals that they were merely pretending to be possessed, tricking the Darknesses. They use their Keyblade to close the gate from their side as well, trapping themselves and the Darknesses in the data world.

Shortly thereafter, Ventus takes a lifeboat into the future, carrying one of the Darknesses deep inside his heart.

Kingdom Hearts III Re Mind
When Sora begins his journey to restore Kairi's heart using the power of waking, he first enters Ventus's heart. When attempting to wake Ventus, he is stopped by an entity referring to itself as "Darkness". Sora questions if "Darkness" is Vanitas based on the latter's last words, but does not get a reply as the entity forms itself into the Dark Inferno χ and battles Sora.

Design
True to its name, Darkness is a miasma of dark energy. Despite claiming to be formless, a humanoid shape with no definable features can be made out within the miasma.

Personality
According to the Master of Masters, Darkness has no sense of reason and is difficult to understand because its thought processes are completely alien to humans. As noted by Brain, however, Darkness is a strategic and calculating force, to the point that even the Master of Masters is seemingly impressed with his foe's cunningness.

Despite Darkness's claims that it wants nothing but to simply exist, it yearns to expand its numbers through the hearts of others, producing Heartless to increase their ranks and shrouding countless worlds with darkness. Darkness seems motivated to have its sense of will remain intact, which has been slowly fading since the abandonment of its physical form, as its efforts to take control of the hearts of others enable it to remain in existence.

Darkness does not understand humans aside from their negative emotions and despises beings with hearts of light. Darkness is capable of feeling emotions, such as rage, demonstrated in its sudden attack on Luxu when he calls its attempts to infect and expand its numbers "pathetic".

Abilities
Darkness has the ability to possess, control, and hide inside of other beings, such as when they possess Ventus. As shown when they impersonate Ava, the Darkness is able to transform their appearance. It can manifest as other forms of darkness, such as Heartless. It also has the ability to become invisible, allowing its actions go unnoticed by others. The Darkness can increase their numbers by indirectly influence the negative thoughts of other people, allowing their hearts to succumb to darkness and giving birth to the Heartless.