Tevintan

The Tevintans were once humans but ended-up being turned into techno-organic beings that now function as a hivemind. This was caused by the nanites that the Henry Flotilla had that was controlled by an AI. The primary directive of the AI was to guarantee the survival of humanity which ultimately turned them into the Tevintans and the world they now inhabit into a techno-organic one as if turned it into a fully functioning, automatic society with each and every bit of the ecosystem and civilization having a certain purpose. Now they seek to assimilate all humans and their subspecies to "guarantee their survival".

Physiology
Their physiology is mostly humanoid with many still have the same human-like features. However, they have glowing, techno-like "veins" that glow blue while having robotic-like eyes. But they do go through a certain transmutation when threaten. They will start to have an appearance similar to a Tyranid genestealer from Warhammer 40,000 but the crests on their heads have a distinguish cyan colored glow alongside their dead, blank eyes. If necessary, they can alter their appearance even further and further until it because something less humanoid and more monstrous. It can be the same with any other organism that has been assimilated that is considered a threat by the hivemind itself. This includes a caste system yet is prone to change.

Society & Culture
Everything is done by a techno-organic AI as every single being under its control as means of "survival". It does use others that it gave part of its essence to maintain control, which resulted in an elite group that assist with the AI's control called, the Hive Collective. They are small in number yet able to control many aspects of living in the hivemind. They also control other necessities such as research, agriculture, military and much more. Yet the AI can seize back control whenever it can if necessary.

Not much about society of the Tevintans. They set people in certain caste when they are born no matter their parent's previous occupation. However, they do change depending on the situation. For example: If you have a group of scientists are stuck in a middle of a fight, they can change their form and become soldiers. If a bunch of builders lack the numbers needed for a project, some of others are recruited to be builders.