A Vower is an intelligent Siphonophore. A colony of independent organisms, it is an animal made of small fungus/mammal hybrids known as zooids. While integrated, the zooid morphs into the organic role needed by the colony. If separated, the zooid will either reconnect or adapt for independent survival.
Perpetually growing and mutating, the zooid produces genetically unique offspring asexually, regardless on whether or not it is integrated. The offspring may be re-integrated into the colony or shed.
As the larger colony animal, the Vower is comprised not of organs but of organic regions as the zooids carry out their functional roles. Unified, each zooid participates in nervous and circulatory processes with no single zooid being critical to the survival of the whole.
All the above adds up to a species that can physically adapt to a wide range of harsh environments and circumstances including the open vacuum of space.
On Incuso, it makes for an oddly tough animal that dominates the research garden it resides in. While it is the Arta's job to feed the Vower's new DNA and violently drive them towards civilization; it is the Vower's evolving natural role to become efficient predators of Arta's eggs and subdue their constant antagonizing.
By design, orgasm induces egg excretion in Artas. So Vowers have developed a biological arsenal to sexually arouse Artas. Intoxicating poisons, instinctual knowledge of erogenous zones, and the organs grown to stimulate them: time and nature has made Vowers masters of Arta sexuality.
In a world that Artas are conditioned to find seductive, they are easy prey for what has become a finely tuned sexual predator.