The Gultanr did eventually come to visit them at Maethrillian, though the Fleet did still swing past their planet to say hello a few times. What surprised them more was that the precognitive dragons brought the Lituni with them. The cat-people were from a neighboring system and hadn't been too far behind them in terms of technology, but even so they must have trusted the Gultanr enough to bring them where they said they would - or had some sort of leverage that ensured they would return safely.
Not that John really expected the dragons to pull anything; they had a good Primas Uperbia right now, one that reminded him of Ferial in that she could do politics very well but at the same time she didn't take anyone's shit.
Silver-Moon greeted the representatives of both species with equal respect and welcomed them to the capital, such as it was. Even though they'd put so much effort into rebuilding her, John rarely had more than a skeleton crew running her, so there were maybe a few thousand people on the whole planet.
This time they brought actual diplomats to talk to the Fleet, and John listened from afar as Audacity swung into a slingshot orbit around a blue giant star, getting ready to launch them out of the star system.
'You sure you don't want to get involved in this, Commander?'
[Positive. You all know what I'm like.]
'Hopeless without Her Grace covering for you? Yeah, we know. And it takes all ninety thousand of us to do the same job.'
[To be fair to you all, things are quite a bit different now than when I was serving in the UNSC.]
'You're still the same person, though, just on a much larger stage.'
[Please don't remind me.]
'Politics… Diplomacy… You can't just shoot your enemies anymore…'
He gave the twins a mental swat, but it just made them both laugh. [I can if they're a clear and present danger.]
'And how often has that happened recently?'
[Mm.]
-------------------------------------------
The Gultanr and the Lituni were first, and there were a few other species not too far behind, most of which John didn't recognize. They were as alien to him as he was to them, but there were a few who brought to mind the various species of the Covenant. The Gultanr were almost the kin of the Sangheili, and the Xevetan reminded him of the Yam'ee, although they were more like mantises than beetles.
It took quite a while to normalize relations between so many species - would have taken even longer if the Fleet hadn't had translation software that enabled communication between even the most disparate species. But even so, bit by bit, generation by generation, they started coming together, interacting amongst themselves.
The Third Ecumene actually got its start as a medical network, after a Lituni virus mutated and killed or severely sickened almost unfathomable numbers of other species. The Lifeworkers all stepped up at once and started working on interspecies vaccination, together with medical teams from all the species in question. They shared bacterial and viral genomes, vaccines, even segments of their own genomes, which led to politicians getting involved because "who knows what they'll really use that information for!"
[You see now why I have no patience for politics.]
'A little bit.'
But after their work saved millions of lives when a Xevetan fungal infection mutated to be hyperlethal to mammalian species, the fury subsided into muttering, and businesspeople started petitioning for real trade treaties, alliances, formal networks between species. There had been individual treaties, of course, but inevitably there was favoritism, smuggling, interspecies crime, with no real way of dealing with it.
So, after quite literally almost five hundred years of negotiations and refinement, the Third Ecumene was born in roughly 45,000 BCE. The Spartan had been out in Audacity for most of it, but as the head of the Fleet, he was still required to come in and sign the charter that Silver-Moon had negotiated with expertise that would have made him envious if he'd had any interest in politics.
Much to his surprise, the Xixi Tuavan leader recognized him. A "male" this time, old, very old, with his successor at his side, a skinny bat-teen still growing into his ears and wings but with many of the same mannerisms as his elder. Ah, said the old Tuavan with a toothless grin, It's you. I wondered if you would come.
[You remember me?] John stepped forward and greeted them with a formal bow, hands spread to show he was (unhappily) unarmed.
Oh yes. My predecessors were careful to keep our memories of you as clear as possible. They knew you were Deathless and hoped we might see you again someday. The Xixi Tuavan returned the bow. I am Tsururun, and this is Aleroum.
[Well met, Aleroum.]
The younger Tuavan bowed too, and grinned brightly.
Your Hive doesn't seem to have grown in the interim.
[We haven't really wanted to expand. No reason to.]
Fair. And now?
[Is that you asking?]
No. I am at peace with death. But there are others who are not - who will seek to take advantage of you for being Deathless. Tsururun shook his head.
[We're putting protocols in place for that - intensive scans and interviews and the like. It took us a long time to get our shit together; we don't want anyone disrupting what we've got.]
Good. I pray that you won't need it, but I suspect that's a futile hope.
-------------------------------------------
The first request came in less than an hour after the ecumene's charter was signed. The Fleet collectively agreed to refuse it out of hand, saying they would not be accepting any new members until the ecumene was firmly established. There were others though, xenobiologists and xenoanthropologists who just wanted to study them, observe them in their "natural habitat", to which John said, "What natural habitat? A fucking Flood Hive? We don't have a 'natural habitat'."
They flat out refused to give anyone samples of their DNA. That was automatic, irrefutable - it was written into the ecumene's charter, they were so serious about it, and the punishment for trafficking any Flood DNA or RNA was incredibly harsh. Some had called it excessively harsh - until the Fleet showed them the horror of the Forerunner-Flood War.
There weren't any complaints after that. There were no containment procedures stringent enough to satisfy the Fleet, not even their own, so they were taking exactly zero chances with it.
But after a time, they did permit some very thoroughly screened scientists to come and observe their own studies of themselves or just to observe them in general, conduct interviews, gather data about their hive mind.
The Spartan was reluctantly persuaded to be interviewed, in a manner of speaking. Really it was just an auditorium full of scientists spamming him with questions, but so many people requested to attend the event that they had to borrow the Ecumenical Council Chamber on Maethrillian to fit everyone.
John died a little inside when he heard that, as he always did on the (admittedly rare) occasion he got called in for press runs, but he powered through it.
But in an interesting and confusing segue, that led him back to the Greater Ark to speak with the Librarian in a contact chamber. "Are we leaving any kind of… I don't know… imprint in humanity about us? About the galaxy at large?"
"We can, if you would like. Though I would have thought you would prefer to speak with them yourselves."
"And go through all of this again with ONI? Absolutely not; I'm not that much of a masochist. Give them… I don't know. Nothing classified. No secrets, nothing that would compromise the security of other worlds. Give them knowledge of the other species, politics, how not to offend the rest of the galaxy - but nothing dangerous. Nothing that would give them an - unfair advantage. Humanity is my home species and I will defend them to my last breath, but that doesn't mean I blindly trust them."
"You do understand that if we're giving them your imprint, you're going to need to know all of those things as well, right?"
John groaned so loudly that those who bore the imprint in question all laughed themselves out of sleep fifty thousand years later.
**********
Xevetan – Zeh-veh-than
Tsururun – Soo-roo-roon
Aleroum – Ah-leh-roh-um