Dream Eater

The 'Dream Eaters] (ドリームイーター) are the new enemies that appear in Kingdom Hearts 3D: Dream Drop Distance. There are two types of Dream Eaters: ones that "eat dreams and plant nightmares", referred to as Nightmare Dream Eaters, and ones that "eat nightmares", referred to as Spirit Dream Eaters. The Dream Eaters are the form darkness takes in the sleeping worlds as Heartless and Nobodies cannot enter.

Kingdom Hearts 3D: Dream Drop Distance
Following the defeat of Ansem, Seeker of Darkness, at Sora's hands, a portion of the worlds attacked by the Heartless remain submerged in sleep. Yen Sid explains that though this means the Heartless cannot reach them, they are instead plagued by Dream Eaters, entities produced by the darkness present in these specific worlds and that seek the worlds' Keyholes. There are two kinds of Dream Eaters, benevolent Spirits and malevolent Nightmares, constantly in conflict with each other.

As part of their Mark of Mastery exam, Sora and Riku journey into the Sleeping Worlds to awaken them, recruiting Spirits to help them in their quest and battling and destroying Nightmares.

Shortly after Sora first meets Neku, the two of them are surrounded by Dream Eaters. Neku summons his own Dream Eater, a Necho Cat, and after the battle, he convinces Sora to partner with the Dream Eaters himself. Joshua suggests the same to Riku after they meet.

Beat summons a Kooma Panda in an attempt to fight Joshua, but it attacks Riku instead.

When Sora and Riku return to Traverse Town, they find that their companions have abandoned using Dream Eaters, and have instead simply banded together with their partners. They also find out that a powerful Nightmare, the Spellican, has been wreaking havoc on the city, and that the participants in the Reaper's Game are tasked with eliminating it. Sora and Riku manage to corner the Nightmare, but it summons several other powerful Nightmares as a diversion, allowing it to escape.

Eventually, Mickey's actions in Symphony of Sorcery accidentally summon the Spellican, who takes control of Mickey and forces him to continually conduct music, causing chaos. However, Sora, with Riku's help, manages to reach the Spellican and defeat him.

Riku eventually makes his way to The World that Never Was, and finds himself face to face with Ansem, who reveals that Riku has been within Sora's own dreams from the beginning as a Dream Eater, in order to protect Sora from the machinations of the new Organization XIII. However, the Organization had already managed to force Sora into a deep sleep.

After defeating Ansem and escaping to the real World that Never Was, Riku finds himself at a dead end, unable to reach the Castle that Never Was, where Sora is trapped. He soon notices Sora's Meow Wow at the entrance to the castle, however, and uses the power of his own Komory Bat to forge a link between the Spirits and ride a Dreamline to the castle.

Following Young Xehanort's defeat at Riku's hands and Sora's rescue, they return to the Mysterious Tower, and Riku dives into Sora's dreams in order to wake him up. In order to defeat the Armored Ventus Nightmare, Riku absorbs the power of all his Spirits and wins in one final clash.

After Sora revives, and Riku is named Keyblade Master, Sora decides to visit the sleeping Traverse Town again, and he is reunited with all of his Spirit friends.

Appearance
Dream Eaters, as stated, have two species — Spirits and Nightmares. They all seem to be animal-based, similar to some Heartless. Spirits are usually light-colored and have black eyes with various shaped pupils. Nightmares are usually darker in coloration, similar to a Heartless's palette, but their glowing eyes are red and get darker towards the center

There are many different types of Dream Eaters, but they can help provide Sora and Riku with abilities as well as aid in combat. Additionally, the colors of your party's Dream Eaters can be customized.

Gameplay
The Dream Eaters in your party level up. While 3 Dream Eaters are allowed to be in your party at one time, only 2 are allowed to be in combat at the same time. The Dream Eaters do not approach anyone and consume dreams in the Realm of Sleep where there are no Heartless.

If Sora/Riku don't use the power of the Dream Eaters, they can't go to the other worlds. Meow Wow is Sora's first Spirit, Komory Bat is Riku's, and Necho Cat appears to be the spirit that Neku Sakuraba gets. The player is also able to change the colors of the Dream Eaters with Paint Guns.

Sora and Riku are both able to make the Dream Eaters with the Dream Pieces they obtain on their adventure. Sacrificing more than the required amount will further assist Sora/Riku in powering the Dream Eater up.

Notes and references
Avale-Rêves Traumfänger