Eater

Eater (イーター) is the name of a type of lifeform in Digimon Story: Cyber Sleuth and one set of antagonists.

Design
All Eaters have elements of. They were designed by Oh!Great.

Digimon Story: Cyber Sleuth
Eaters are dangerous creatures who inhabit the reaches of Cyberspace EDEN. One ambushes Aiba, Nokia Shiramine, Arata Sanada, and their partners while in Kowloon Lv. 1. Aiba and Nokia hold it off while Arata activates an old terminal, through which they escape. Aiba, however, is unable to make it in time and ends up captured. By some miracle, they are able to log out but as a half-digital entity, giving them potent hacking abilities as well as the power to Connect Jump into digital spaces.

Eaters continue to be a recurring threat, as they feast on human data while in Cyberspace EDEN. They are behind EDEN Syndrome, as their consumption of human mental data leaves the original bodies comatose. They can also be found at the cores of Digital Shifts, where digital space bleeds into the Real World. Defeating them ceases the Digital Shift as well. Arata ends up investigating the Eaters with Aiba's help, eventually coming across the researcher Akemi Suedou.

Eaters turn out to not only have infested the Real World. They attacked the Digital World as well, turning it into a hellish landscape on the brink of destruction and prompting the to invade the human world. reveals that Eaters only are as they are because of the influence of humanity. The Royal Knights become divided on how to handle the Eater threat; one faction seeks to exterminate humanity while the other wishes for co-existence and unity. In the course of exterminating humanity, Crusadermon causes a giant Digital Shift that encompasses all of Tokyo, unleashing Eaters into the human world as well.

During the course of Aiba's battle to stop the Royal Knights, a hidden truth is revealed. When the first EDEN beta test occurred, Aiba, Nokia, Arata, Yuuko Kamishiro, and Yuugo Kamishiro managed to find a way into the Digital World. There, they encountered an Eater, who absorbed Yuugo and causing him to be the first sufferer of EDEN Syndrome. Eaters exist as a unified network that is constantly in communication with each other. Yuugo became part of that gestalt, slowing the Eaters' corruption of the world while at the same time causing them to seek out data to consume.

Eventually, the extermination faction of the Royal Knights is defeated. Suedou comes up with a plan to send the Eaters back to the Digital World to save humanity. He also reveals that the Eaters have a main unit titled the Mother Eater, which, if eliminated, would also stop the other Eaters. Yuugo is integrated with this core, so Aiba and their friends resolve to enter the Digital World, where the Mother Eater has merged with 's core, and end the threat once and for all. Fighting their way through King Drasil's defensive programs, Aiba manages to rescue Yuugo. Unfortunately, removing him from the Mother Eater means that the Eaters' erosion of the worlds will only accelerate. Suedou steps in at this moment, definitively showing that he has been working toward his own goals the entire time. He wishes to become one with the Mother Eater and King Drasil, merging everything together to create a new world without sorrow. Aiba must then take down the Mother Eater after Suedou merges with it and, despite the erosion they personally suffered through contact with Eaters, attempts to save Suedou as well. Seeing Aiba's actions and emotions, Suedou has an epiphany and decides to see what future Aiba will create.

Suedou reveals the Eater's true nature to Aiba. Eaters exist in a higher dimensional space that links worlds together. Their job is to observe and send data back to the higher dimension. When they came into contact with Cyberspace EDEN, they took on form and substance that corrupted them from their original goal. Suedou uses King Drasil's power to reformat the Eaters back to their original harmless form. These forms are like spheres of light, and speculates that phenomena such as  and s were actually Eaters who became visible due to Digital Waves. Nevertheless, Eaters are now harmless, and the possibility of them once again being corrupted is remote enough to be essentially impossible.

Digimon Story: Cyber Sleuth (manga)
When Takumi is fighting some Demons members, an Eater suddenly appears and absorbs the Hacker group. When reporting to Kyoko, Takumi remembers the Eater who attacked him in Kowloon Lv. 1.

Digimon Story: Cyber Sleuth - Hacker's Memory
Keisuke Amasawa and Ryuji Mishima are chasing down Youji Shiga as they believe him to be the one to steal Keisuke's account. After stopping him from capturing and  and then defeating his Golemon they get access to his digivice and find he wasn't responsible for stealing his account. Suddenly, an Eater appears and attacks Youji. Ryuji and Keisuke flee but when Keisuke shows concern for him, Ryuji states it's fine because "that monster just destroys accounts". In reality, it causes Youji to fall victim to Eden Syndrome.

Later on whilst in Kowloon, after befriending Arata Sanada, the duo suddenly come across an Eater and manage to defeat it before it causes any harm. Arata later hires Keisuke to help him find his friend who had gotten lost in a museum. They find him about to be attacked by Eaters but manage to save him just in time.

Keisuke and Erika Mishima are in Shinjuku when it suddenly turns into a Digital Shift. They wander around and realise Digimon have suddenly shown up and battle their way through, eventually finding Akemi Suedou. After discussing the unusual events, Erika winds up naming it a Digital Shift, though whilst talking an Eater shows up. Keisuke defeats it, protecting the three of them - however the Eater isn't killed and flees further into the shift. Keisuke is about to chase it, however Erika passes out, leading Keisuke to take her out of the shift and to the hospital instead. Aiba and Arata arrive shortly afterwards, which leads to them meeting Akemi for the first time and being the ones to kill the rampaging Eater.

In Under Zero, when summons a massive group of Eaters to attack the group of hackers that had been gathered, Hudie defeat large amounts of them. However, one of them is about to attack Ryuji, so Chitose Imai manages to push hum out of the way, leading Chitose to be attacked and contract Eden Syndrome in his place. This leads to the events of being freed from Under Zero and it and Ryuji terrorising both the Human World and Eden.

Erika comes up with a plan and manages to hack an Eater, after they searched for one using tools provided by Suedou. Erika manages to use the data she found to access the Eater World, in which her, Keisuke and come across Yuugo Kamishiro. After explaining the situation to Yuugo, he allows them to locate Chitose's memory data. They then upload the data back into Chitose's mind, causing him to be the only person to ever recover from Eden Syndrome.

Erika later uses the same data to create Eaters of her own, known as Eater Bits. They however turn on her after she collapses following the defeat of Arcadiamon, to create Eater Legion, who escapes and attempts to find its way into the Digital World. This leads all of the Eaters to infiltrate Eden, shutting it down. Hudie, due to the help of Yu Nogi and the other hacking teams manage to access Eden, allowing Hudie access. They defeat countless Eaters and eventually come across Eater Legion. Keisuke and kill Eater Legion, Hudiemon being the remaining corrupted parts of Erika's memories, but a massive group of Eaters merge with the remains of her memory banks to become Eater EDEN. Luckily, this is also has defeated by Hudie, and shortly afterward the Eaters are all erased due to the actions of Aiba and Suedo against the Mother Eater.