The Vessels are a new type of Enemy that debut and are specific to Kingdom Hearts: Echoes. They are the only enemies of the series known to be Light-Alligned, and their presence in the world serves as one of the series' most important plotlines.
The Vessels are creatures made up of the Light of Kingdom Hearts itself, their existence fueled by it's power. They were created when Kingdom Hearts grew an intelligence of it's own from the massive amount of Hearts that have been fed to it since the Keyblade Wars first began. The intelligence was at first benevolent, and was responsible for bringing the Light to the Worlds. However, when the Keyblade Wars began, the Hearts of Keybladers that fought for the Dark began to enter it, corrupting it. When the Keyblade Wars ended, the intelligence was so conflicted, that it thrust it's newfound Darkness into it's own Realm (The Realm of Darkness) and shut the rest of itself away in order to protect itself and the Worlds from further harm. This marked the beginning of the Worlds' seperation, and the reason why barriers prevent them from joining together.
However, even though the intelligence's power was gone, it still watched over the occurences throughout the series. It saw the repetition of history through the actions of Xehanort's Heartless and Xemnas, the leader of Organization XIII. It also saw the actions of Sora, Riku, and their troupe. It knew that sooner of later, another Keyblade War, smaller on scale, but just as deadly would begin. After Xehanort's defeat at the hands of Master Sora, the intelligence decided that to prevent another War, one side would have to conquer the Worlds completely. The Heartless, which were born from Kingdom Heart's Darkness (which came from the Hearts of the Dark Wielders, and in turn, the Realm of Darkness) were beginning to die out, and this was it's only chance. If it could usher in a new Age of Light, it could have enough power to destroy it's Dark half comepletely, and return the Light to the Worlds. By using the power of absolute Light, it created the Vessels: Embodiments of it's own power. It intended on retaking the Worlds and ushering in a new Age of Light...any way it could.
The symbol for the Vessels has a double meaning. The black coloration of it's lines refer to the Darkness within Kingdom Hearts, while the white patches represent the intelligence of Light ekeing it's way out into the open.
The symbol's cracked nature refers to Kingdom Hearts' confliction between the Light it seeks to give and the Darkness that it is forced to tolerate.
The Vessels behave similarly to the Heartless. Vessels ARE their namesake: merely Vessels containing the power of Kingdom Hearts. They are also hostile to all beings, and like Heartless, wish to assimilate others to the Light, by force, if necessary. They also see to be able to feel very basic emotions, such as happiness or sadness. Despite this though, their primary goal of retaking the Worlds is paramount.
Even though Light and Dark are opposing elements, they cannot live without the other. This is why the Vessels help the Heartless. The two species are both linked to Kingdom Hearts, and if one dies out completely, then they both do. One could see this as more of a tolerance, rather than an alliance.
Many Vessels are formed whenever a Vessel assimilates a being or object. However, they can also be formed whenever a person with high ambition is either dead or returned to the Light. Vessels are fueled by not only the Light of Kingdom Hearts, but are also fueled by the failed ambitions and dreams of a being. This can range from unbridled greed to failing to protect a loved one or being unable to reach a lifelong goal. Similarly, Vessels are also attracted to those with ambition in their Heart, making those who strive for too much targets of assimilation and/or Vessel attack. In extremely rare cases, Vessels will sometimes fight alongside those with high ambition. This primarily applies to Villains, though there are exceptions. However, once the person's current objective has been fuilfilled, they will, like the Heartless, turn on their "masters." As long as the person has ambition in their Heart, Vessels will always be present.
Vessel Codex Entries
When reading the Fanfiction.net adaption of the game, one will notice that the names of the enemies are simplistic and downright blunt and unappealing. This is due to the fact that the developers write the game as though one is playing it. Therefore, the simplistic names are to be assumed from the Player's point of view, rather than the game's official names for them. The real names are listed below. (Note: As Chapters of the story are finished and posted, the list will be updated to reflect new additions and changes.)
Ghost - The primary and most basic Vessel. Can phase in and out of reality at will, often using sneak attacks as a common tactic.
Zombie - The Vessels' answer to the Soldier Heartless. They shuffle around, trying to damage players with their claws.
Midnight Moonlight (Called "Moon" in story) - What goes around comes around. These guys are living proof. These Moon-shaped enemies use their bodies as makeshift boomerangs, trying to cut the player into ribbons. Evasion is key, as they tend to announce their attacks.
Big Boy (Called "Bruiser" in story) - The bigger they are, the harder they hurt. These guys, while slow pack quite the punch. Stick to magic or long-range attacks to take these "superheroes" down. When their assisting other enemies, take them out first, or you'll find yourself eating a LOT of attacks.
Wind-Up Toy (Called "Robot" in story) - These guys will not be saying "Domo Arigato." These guys like to attack players with swipes of their arms and mini-lasers from their neon eyes. They should learn to WATCH THEIR BACKS....Hint, hint. Just be careful of their tantrums when you find their secret out with the "Deactivate" command. Make theirs a "shocking" ending....Another hint.
Crazy Cog (Called "Cog" in story) - These guys just love to fry unsuspecting victims with their eye-lasers. Ride them with the "Control" Reaction Command so they can attack their buddies instead. Just be careful not to fall off!
Mini-Winger (Called "Spaceship" in story) - If theyr'e anything, they are accurate. Wingers like to lock onto their targets and pelt them with lasers. And if that doesn't work, a full-on charge always gets the job done. Magic is the best way to deal with these things, since they like to bob and weave around in the air.
Loyal Larry - These guys are unique to the Enterprise. These officers are NOT their namesake and will attack anything with their fake Phasers. Transfer them out of the Enterprise and directly to oblivion. Just be careful not to be reduced to atoms by their Phaser blasts.
Prober (Called "Alien" in story) - Unique to the Enterprise, they came to this planet looking for intelligent life.....Looks like they made a mistake, and theyr'e none too happy. Their small size makes them difficult to hit. Magic works extremely well on these little eyesores. Be on the defensive, because they can burrow into the ground and stun anyone who wanders too close to the bulging section of ground they hide in.
Planet Eater - A massive Vessel that attacked the Enterprise above the planet Halka, intending to disrupt the negotiations. However, the combined efforts of Locke and the Enterprise sent the creature packing at warp speed.
Copycat - A Vessel that attacked the Enterprise Main Bridge. It's ability to make copies of itself served as the perfect distraction for Iskonis to release the Mirror Universe's landing party. Aios thought he might've been able to talk to it somehow.....but it destroyed itself before he could get the chance.
Noble Steed - A Vessel that was summoned by Iskonis to fight alongside Mirror Kirk aboard the Enterprise. It tried to use it's horn-sword and it's blade-like hooves to make mincemeat out of Aios and Spock. However, the duo managed to put this horse out to pasture.
More coming soon....