I've been trying to collate everything we've been told about the BP-verse Shivans and the Vishnans, by the Shivans/Vishnans:
The Shivans, first off, are incomprehensibly old, first manifesting 5 billion years ago, and are implied to be somehow connected to the very fabric of reality itself.
Ken: "They were not made. They were calculated."
Shivans: "We slept beneath the waves before the first Brahman rose from the ash of the Dawn War. Before even the first stars kindled in the hearth of night. [...] Only we are eternal."
The Vishnans are more recent, some other race that has risen to, or close to, the Shivans' level. The Shivans mention watching them develop.
Shivnas: "The Brahman rose. The Brahman died. In their death we watched your making..."
The Brahmans are dead. The Shivans didn't seem to have any problem with them, maybe even approved of them.
There was something called "The Dawn War" which resulted in the birth (not death, the Shivans were kind of specific about this) of the Brahman race.
Shivans: "...the first Brahman rose from the ash of the Dawn War."
There was some kind of Apocalypse long ago. The universe survived, and the Shivans and Vishnans do not want to see it happen again. The Brahmans had created the Terminal Protocol to ensure a Second Apocalypse doesn't happen. Part of this protocol involves culling intelligent species that "fail" it. Both the Shivans and the Vishnans seem to think this Protocol is a good idea, and have been carrying out even after the Brahmans died.
The two uber-races began to differ in how they interpreted the Protocol. The Vishnans wanted to guide humanity to some unknown purpose. The Shivans thought this action undermined what they'd been doing for billenia. Hence their fight in Age of Aquarius.
Shivans: "We reject your judgment. We reject your mercy. By using them, you endanger the work of eons."
Since then, the two uber-races seem to have reversed their opinions. The Vishnans are believed to now consider humanity a failure due to the Sol War, but the Shivans now think that humanity can accomplish something that even they cannot. Something that will help avert the Second Apocalypse.
Ken: "But [the Vishnans] see the civil war as a mark of unforgivable failure. They have ordered a cull."
Ken: "The Shivans have a use for humanity. They will grant us survival...and in exchange, we will do the one thing that they cannot."
And for some reason all of this pivots on the UEF. Their Ubuntu ideology makes them unique and special in some way to both the Vishnans and Shivans.
Now here's where it gets interesting to me. The Vishnans apparently do not know about Ken, and do not know about the pact Bosch struck with the Shivans. The Shivans do not want them to find out. Perhaps that is the real reason why they were interfering in Age of Aquarius, removing the Vishnans' chosen "Wanderer" from the equation so he couldn't find out (and the Vishnans through him).
What does all this add up to? No idea. We're still missing key parts of the equation. What was the First Apocalypse? What is the Second Apocalypse? What is the nature of the potential that the uber-races see in humanity? What is the fundamental nature of the Shivans? What is Project Shambhala?
There are also some terms I do not understand. Most of the Shivan technobabble from the nodes ends up being either philosophical or medical terms (taking the metaphor that the Shivans are a "immune system" for the universe). "Noösphere" is a sphere of thought (compare "biosphere" or "atmosphere").
"Ontovoric" is not a word, insists all dictionaries I consult, though I guess it means "that which devours existence" (from "onto-" = "existence/being/is" and "-vore" = "devour"... admittedly, that's mixing Latin and Greek roots). By taking a similar approach, "panontos" (also not a word) may mean "totality of existence" ("pan-" = "everything" , "ontos" = "existence/being/is"). "Holocide" seems to mean "killing of the whole" ("holo-" = "whole" and "-cide" = "killing"... again mixing Latin and Greek). Any other/better ideas on this?