The Ret-ti-Senek, or rat-ants, are something of a mystery to the rest of Crinos. They live in isolation from other Verdimm, their hive-like mounds rising in the distant northeastern reaches of the land. Their race is divided up into castes: workers, warriors, drones and queens. Workers are the most often seen; each is the size of a large dog or a small colt, vaguely ant-link in form, but with rat eyes as well as compound ones, as well as dull gray fur growing from their carapaces and flexible, whiplike tails. Warriors are larger, with darker fur and powerful mandibles. The rarely-seen drones are gaunt, insectile figures who can walk upright and which have been known to work magic. Queens have never been seen.

Each Ret-ti-Senek hive has a single queen, whose symbol is painted on the bodies of its offspring. Some of the most commonly seen hives are Crimson Spiral, Azure Circle, and Silver Triangle. The total number of rat-ant hives is unknown, but at least thiry are visible from the southern edge of their domain.

The Rets are omnivores. Workers range far and wide across the plains of the north and east to gather organic matter: roots, leaves, nuts, tubers, and so on. They are rarely able to kill their own meat, but are often seen scavenging the remnants of another's kill. Parties of workers sometimes venture outside the Ret-ti-Senek territorial range in order to feed the hive.

Outside of their great earthen mounds, the Ret-ti-Senek are only seen in their Khiulnter forms. Darkstalker claims that he once entered a Ret mound by stealth and saw them in their Dimoh forms. Others have claimed that the Ret-ti-Senek are not true Verdimm, but are animals with only one form. Typically, the Rets themselves have not commented on this.

The Ret-ti-Senek employ a strange language of clicks and scents that is difficult to comprehend, and communications with them is fraught with difficulty. In addition, the workers and warriors are not very intelligent. On the other hand, the empathic/telepathic links between rat-ants of a given tribe is extremely strong, allowing them to act in perfect unison. When a hive's group mind focuses on a particular action, its members can suddenly evince a strange, almost frightening intelligence.