Another thing I was thinking of while on the trip were Lenyxs.
They are a huge liontaur-like species that went extinct years ago (before Delphteans were created). They are the Flowid that branched off from the Ather branch and the branch the Vactyr come from. As a Flowid, they were sentient and had a culture heavily influenced by religious belief. They refrained from technology and violence believing a simple life living as one with the planet would guarantee peace and a life of dignity.
Lenyxs hunted the local megafauna of the plains and maintained the local flora for consumption and medicine. They only used Flow when necessary- viewing the power it grants as a temptation. It was primarily for healing the sick and injured, but only in severe situations. They “burnt-off” the excess Flow as they grew, which lead to their excessive size. Lenyxs never stopped growing as they got older as a result.
They were alive in the time all Flowids could both produce and control Flow. They were wiped out in the same event that destroyed the Ather’s ability to produce their own Flow. The being that committed these atrocities, Glacnix, saw the Lenyxs as “nothing.” Glacnix, in every sense of the word, was a monster of a Vactyr who figured out how to make his Flow go into a positive feedback loop that gave him near unlimited control of it. It took the entire council of the Vactyr to seal him away and they took on the job of fixing the damage he wrought.
This! is not something currently within their power. No one else has figured out how he achieved the feedback loop, and they view such power as recklessly dangerous. They created the position of Keeper- It ensures a single seat on the council that can’t vote but can veto. As positions on the council are determined by who is in charge of their city, they gave whoever holds that seat a village of no citizens. This is to reduce their influence over others and decisions as much as possible while they work on becoming a more powerful Flow user. In this process, the person that holds the position loses their name and ends up known only as Keeper.
The current Keeper isn’t fully alone as his village has been overrun by Lost that abandoned their posts on Hirud. He takes care of them like any other citizen, even though he doesn’t understand them. He also assists any Liberated that visits with healing, removal of the parasite, and other services (such as transing their genders).
As a note: Keeper is a strong Flow user, but he will never get that feedback loop. If he were presented with the answer to what he is duty-bound to seek, he’d have to be forced to do it out of moral obligation.
However another Vactyr figured it out, mostly because he lacks morals.