These majestic entities are those who are running the Stellar Institute of Caring & Co-Existence (SIoC&C). The first one, Tethys, was mutated from the computer of a travelling diplomat-ship with its personality based on scientific/diplomatic data logs. When interacting with flesh-and-blood sapients, the Tethys sisters are embodied as biomechanoid whale-snakes with friendly-looking faces.
Their attitude on cosmos is that everything, from worlds to individuals, have a unique value that must be nurtured. The Sisters are very militant about it as they tend to interfere in others business and have their own military power to back up their authority, with force only being used as a last resort. They name themselves after health deities or fictional doctors, having names like Asclepius, Brighid, Heka, and Sirona. Even if most of them appreciate original uplifting and terraforming, most of the Tethys-sisters are not interested in making their own creations and are happy with being adoptive-parents to the creatures they save. As patrolling robots, the Sisters are nomadic beings that meet each other rarely but they eagerly network with each other when they do.

This is the most well developed one of potentially many robot `species´ in "Amazon B.E.". I was very influenced by "Star Trek: The Next Generation", with the episode "Emergence" being the inspiration for the backstory of my AI mer-nagas. I also took the Sisters robotic design as an excuse to play with more cartoony/anime style. But I have not decided to what extent the Sisters robot-bodies are life-like, if they have nanobots or not.