Iterator

Iterators are semi-biological Artificial Intelligences used by the Ancients with the only intended function is to solve the Great Problem. Only two iterators are accessible in-game: Looks to the Moon, and Five Pebbles. Several other Iterators are mentioned in-game through pearls.

Description
Iterators are massive metal superstructures, sometimes called "cans", suspended high above the ground by number of supports. The undersides of the superstructures are frequented by periodic lethal green electric storms. A city can be found on top of each Iterator.

In-game lore strongly suggests that Iterator cans produce the water vapor & cloud layer surrounding them, and as such are responsible for the heavy rainfall of the game world.

Each superstructure contains an internal zero-gravity environment populated with Neuron Flies. There is also a central iterator "puppet" which can be directly communicated with.

Looks to the Moon / "Big Sister Moon"
As the senior Iterator of the Local Group, Moon once often acted as the decision maker for her neighboring Iterators. Her interactions with the Slugcat show her to be kind and considerate, and yet rather assertive as well. Her can collapsed sometime after Five Pebbles, her closest neighboring Iterator, began leeching off her water supply, leaving her in an almost catatonic state.

Moon is located in the far right of Shoreline, in the ruined Looks to the Moon facility. Slugcat is able to understand her speech once given the mark of communication by Five Pebbles. Her dialogue changes depending on the being played. If brought pearls of any kind, she will attempt to read them—revealing much of the game's hidden lore.

Five Pebbles / "Erratic Pulse"
A calm yet cynical Iterator, Five Pebbles is perhaps the most unpredictable of the entire Local Group. He is responsible for the cataclysmic rainstorms that threaten the Slugcat.

Pebbles has grown resentful of the "Great Problem" the Iterators are forced to calculate, and hopes to find a fate more suited for his desires. Always holding an interest in the idea of ascension, Pebbles quickly gained great interest in the subject when Sliver of Straw released the Triple Affirmative. Pebbles went undercover in several "Sliverist" groups with the alias "Erratic Pulse". He has held plenty of experiments in attempts to achieve what Straw achieved, but all have ended in failure.

The worst mistake occurred when Pebbles attempted to circumvent the self-destruction taboo by rewriting his own genomes. The result was "The Rot", which continues to plague Pebbles to this day. In his desperation to get rid of it, Pebbles flushed out his superstructure, dumping trash onto the surface—creating the Garbage Wastes. Sadly, his efforts were in vain. Distressed, he began to use even Moon's water reserves in attempts to flush the Rot out, severely damaging her in the process. Due to a senior order from Moon moments before she collapsed, he was forced to stop. He currently desperately attempts to destroy the Rot infection, but has no idea how to do so.

No Significant Harassment
Only ever known as the jokester of the Local Group, NSH doesn't have much said about them. Their sense of humour is noted in several pearls. They don't take the "Great Problem", or any problem for that matter, very seriously. However, if is able to reach Looks to the Moon with both the Green Neuron and its starting pearl, it will be revealed that NSH was responsible for reviving Moon by sending the Hunter to her aid. The rare Green Overseer is believed to belong to NSH.

Seven Red Suns
An Iterator in the Local Group. SRS is a close friend to Five Pebbles. Especially when he develops the Rot. Similar to Pebbles, Suns is rather cynical in their views, even going as far to pronounce the futility of the Iterators and their attempts to solve the "Great Problem".

was sent by SRS to establish contact with and  in light of their abrupt disappearance from the communication network, and SRS themselves are seen along with Spearmaster in their character art after having delivered Moon's message.

Sliver of Straw
A sort of saintly Iterator amongst the rest for somehow achieving self-destruction. She broadcasted the “Triple Affirmative” to the rest of the Iterators shortly before dying: Affirmative that a solution has been found, affirmative that the solution is portable, and affirmative that a technical implementation is possible and generally applicable. Ever since her passing, Iterators have collaborated and convened in chatrooms in attempts to reproduce her conditions. All attempts so far have failed, however.

Grey Wind / "Chasing Wind"
An Iterator in the Local Group. Though often unmentioned in pearls, CW seems to be a participator in "Sliverist" groups. They grew suspicious of an "Erratic Pulse" speaking of personal Ascension in a conversation, and mentioned it to several members of the Local Group. CW contacted Seven Red Suns in an attempt to help Five Pebbles.

Unparalleled Innocence
Though barely mentioned in pearls, Innocence is one of Pebbles' neighbors. They were responsible for taking pictures of Pebbles' condition, which "were then made public in the Local Group".

History
As their name implies, Iterators were created by the Ancients to iterate—try, try again in solving the Great Problem. They also were tasked with taking control of the Ancients' daily troubles in an effort to help the people achieve Ascension easily. Iterators were created after the Void Fluid revolution, which allowed the Ancients to construct these massive superstructures with ease—hundreds, perhaps even thousands of Iterators were created during this time. Iterators would bring food, water, energy, and other necessities to the cities on their cans. After the last of the Ancients were gone, the Iterators began to work on two different issues—one assigned to them by their creators, and the other brought to attention by the Iterators.

The first issue is the "Great Problem"—the matter of helping "lesser beings", such as Lizards or Slugcats, ascend. This is a difficult issue—after all, most creatures in the current state of the world are fighting for their survival every cycle, and thus are often completely unenlightened. In addition, the Iterators have no reliable way to speak to or contact these "lesser beings", except in the case of the Overseers. Unfortunately, the relative focus on this issue was nigh completely abandoned once the second issue came into play.

The second issue is the matter of Iterators achieving ascension. Though at first considered completely impossible, Iterators began to speculate and convene with one another on how one could achieve such a feat. Interest peaked when Sliver of Straw, a deceased Iterator, released a "Triple Affirmative"—affirmative that a solution has been found, affirmative that the solution is portable, and affirmative that a technical implementation is possible and generally applicable, according to Moon. Due to Straw's mysterious death shortly after sending the signal, no Iterator knows what her solution was. Many iterators have tried to replicate her solution, but all have failed.

Trivia

 * The Rot seems to be nothing new. Seeing how the other Iterators knew about it when Pebble's case was discovered, it's likely that past Iterators have attempted and failed the same thing as him.
 * Five Pebbles seems to grow increasingly frustrated as more creatures show up in their quests for ascension, specifically Slugcats. By the time The Monk arrives, he wishes they'd just leave him alone.
 * At the uppermost region of The Wall, it is possible to make out buildings in the distance. These are the cans of other Iterators. In total, they number at least 10. Adding to this number Five Pebbles and Looks to the Moon, who we can assume is not visible here due to her subregion being so far below Five Pebbles', 12 total Iterators are potentially featured in-game through more than just text.