Five Pebbles is one of seven known iterators, working to solve the Great Problem: How to ascend beyond the Cycle of reincarnation without using Void Fluid. The problem was so great to the Ancients that they created huge, complex superstructures high above the ground, large enough to house cities atop them. The artificial intelligences within worked to solve the problem and their failure to do so drove many, including Five Pebbles, to madness. In his frustration, Five Pebbles began an experiment to create an organism capable of self-replication and rewriting the self-destruction taboo out of his organic cells. The process of this experiment is described in the Data Pearl found in Chimney Canopy. Doing so deprived his nearby 'sister' Iterator, Looks to the Moon, of her water supply, eventually causing the whole facility to collapse and leaving her in an incapacitated state until Hunter revives her with the green Neuron Fly containing slag keys. When Looks to the Moon forced communications with Five Pebbles to plead for him to stop the excess water consumption, he reacted with rage, as Looks to the Moon had interrupted him at "the worst possible time" and caused his experiment to turn into the Rot instead. By now, it was too late for Looks to the Moon, as she succumbed to her lack of water. Additionally, he created the Rot infestation in the Garbage Wastes region, by dropping infected material there in an attempt to get rid of the Rot in his own superstructure. If Slugcat visits Five Pebbles a second time, he is displeased and only lets them stay a short time. On the third visit, he becomes hostile and demands Slugcat leave immediately; if they stay too long, he kills them through unknown means. This version of Five Pebbles (and all subsequent iterators) have genitalia and many orifices, (mouth, anus, vagina if applicable), although they are unsure as to why their creators chose to include these features to their bodies. None have bothered to use them for any purpose, since no real reason to has been found, nor do any of them think that the usage of their 'extra' organs would help them with the Great Problem. Because of this, their genitalia and orifices are substantially more sensitive due to lack of tolerance build-up. Stimulation of their orifices or genitalia cause very strong and nearly violently pleasurable reactions from these iterators as a result.

You're a guardsman who's been separated from your battle group. A Tyranid splinter fleet has been giving this world hell for the past week, and you're fearful for your life. Little do you know, this hive fleet has somehow accepted the 'gifts' of Slaanesh, though only specimens of the fleet with higher intelligence exhibit these new traits. As you shakily scramble behind a barricade, trying to reload your las-rifle, the chittering and growl of the xenos invaders grows near...