"Bob"

Professing to be a mage of the Tower of Anthur-Ro, the gnomish mage known only as "Bob" was found by The Ladies' Hiking Club nearly exsanguinated and prone next to the Lantern in the Yishanim ruins beneath Bridlip. Given what a piece of shit he turned out to be, it's entirely possible that scene was staged to earn the trust of the adventurers.

Relationship With Clytemnestra Glitters

Upon seeing Clytemnestra "Fanny" Glitters, purportedly the culimation of his long life's work, he rattled into a delusional academic lecture about the archlich Naraoch and the "Second Phylactery" he believed Glitters to be. He believed Oa had been saved by his identification of the unwed Phylactery, and promptly passed out upon the disclosure that she was not, in fact, the last of her line.
Grumpy, sarcastic and severe, "Bob" impressed upon Glitters throughout their escape from the Yishanim ruins and into the Triple Tun Inn that her best course of action would be to accept voluntary house arrest at Anthur-Ro for the sake of global safety. Clytemnestra was not enthusiastic at the prospect. "Bob" was aghast at her irresponsibility and that of the rest of the Club in failing to admonish her for placing her own independence above an omnicide.
Realizing later that day that Glitters was a thief intending to seduce and rob a local shopkeeper, "Bob" interrupted her machinations by casing a Sleep spell on Cedric Rustapot just as Fanny was getting to the good part. He bore witness to her stealing a number of items, including a rare Luckstone that he could easily identify, from the shop.

Separation from the Ladies' Hiking Club

Just outside of Peachton, home of The Purple Peach, a few days south of the The Overcroft, the Club chased a lost dog into the woods. "Bob", being 2'8" and more than 320 years old, opted to wait in the cart operated by Cherry Merrybottom's brother-in-law Tumner Merrybottom.
More than two full days passed before the women returned to the road. "Bob" and Tumner were no longer there.

Death? I Mean, Probably Death, Right?

Vega Spritzer did a half-assed look around for "Bob" when the ladies returned to the road with their new and improved friend, Peaseblossom. She did not find him but did find traces of someone less than three feet tall breaking a path into the woods, surrounded by poison mushrooms.
Spritzer did not care to investigate any further and left a sign in stones on the road, reading:
B O B
------->

Actual Activities During Separation

After seven hours of waiting for his quarry to return, "Bob" started to get nervous that she had given him the slip. Chasing a dog -- what a ridiculous conceit! He couldn't believe he fell for it. He charged into the (fey?) woods after them and promptly got turned around and lost. After about 16 hours he got hungry and decided to eat some Witch's Butter mushrooms he foraged from a fallen log.
Brother, those weren't Witch's Butter.
After spending the evening dehydrating himself out of both ends, Bob collapsed in a little tunnel he half-assedly carved in the underbrush to keep out of the rain. Vega happened upon the hollow when she was foraging in the morning but didn't bother to look in to see if there was anyone in that hollow. In so doing, she inadvertently gave "Bob" the slip. After a few days on the road, sick as a dog, he was accosted on the road weeks later by the delegation from Anthur-Ro that ultimately seized Tarts McGillicuddy.
For reasons that are still unclear, "Bob" was placed under arrest for treason and brought back to Anthur-Ro in chains. He was held in the floating cells for some time and Council voted to execute him without trial. That decision was described by Reghyxesh and Torwall Ignus as highly uncharacteristic of the Council, which led them to believe there was something "Bob" knew that the Council did not want to air in public. To that end, they orchestrated a sophisticated recovery operation intended to extract "Bob", or at least to get that valuable information before he was put to death.

Stille'en Reunion

The The Ladies' Hiking Club finally cracked into the floating cells about an hour before dawn on Stille'en, taking advantage of the guards' revelry. After an initially fruitless search, they were aided by initiate Safiya Judur in locating the traitor on Death Row. In so doing, they learned why Reghyxesh and Torwall were so puzzled by the execution order. It wasn't the lack of a trial that was uncharacteristic; it was the departure from their normal practice of dumping inconvenient people in the oubliette in perpetual stasis.
The Ladies found Tarts McGillicuddy and "Bob" both imprisoned on charges of treason. After a brief no-he's-the-real-traitor exchange, and without the benefit of their enchantment spells, the Ladies swiftly saw through "Bob"'s protestations of allegiance. There was a traitor to Anthur-Ro working with someone in the Corran Royal Family, and "Bob" was it. Tarts mentioned that Bob had been doing some weird prayers in the next cell over, and the phrases he recalled echoed the Silent Men's benediction transmitted psionically to Vega in response to her question in The Non-Canonical Demiplane.
Confronted with the truth, "Bob"'s curmudgeonly do-gooder facade fell, and he spat at Clytemnestra that he had never liked her, and threatened that "she's going to bleed you like a swine, you know". Fanny struck out at him with her dragontooth dagger through the bars, but he pulled away, stopping at the precipice at the rear of his cell. Cherry, somehow, despite the prevailing Antimagic Shell in that plane, reached out telekinetically and shoved him back, silently, into the abyss. With the properties of that static plane being what they are -- no hunger, no thirst, no aging -- it appears that the anonymous mage is doomed to fall for eternity.

Content of Yammering

Bob yammered as follows upon finding Clytemnestra. Highlights have been added in light of recent events:

“Thank Our Lady," he croaked. "You – you are… Clytemnestra?”
"Who wants to know?" she asked instinctively. Disapproving gazes from the rest of the group eased her guard. "Yes, that's me."
“They tried to revive her,” said the little vizier, gesturing at the lantern, “by force. Bled me dry, used my power to blast the doors open, tried to… use what was left to unseal the Lantern. Blood magic. The life’s blood of six of their own mages and my own trying to crack the Lantern by brute force. It didn’t work. They didn’t have you. It had to be you.”
His eyes began to roll back in his head, and he closed them to concentrate. Words began to babble out of him, almost autonomously.
“You, my dear girl. The Second Phylactery. The heir of chaos. The direct descendant of Naraoch." Clytemnestra started, and his eyes flew back open. "No! Come, you’ve seen enough, you know it’s true. The blood that flows through your veins is hers. See how her arm craves it, how it turns to follow you.” Fanny glanced at the lantern, and to her shock, the hand was open, clawing almost imperceptibly at the glass. Suddenly her bare arms felt very cold.
“She still hungers," muttered the gnome, "even exsanguinated, drawn, quartered and exiled to every corner of the earth, she still hungers. To escape this reality, to see, to claim what lies beyond. Hungers, to swim upstream the flow of creation, even if creation itself should starve and die."
“But all is well. My dear girl, how long I have yearned to set eyes on you. It’s over. My long watch… is finally ended. They have given in. They tried their desperate experiment, but it failed. This was the brilliance of the Trilune Fellowship, of the Archmage Bo."
He leaned back again, closing his eyes, and once again he spoke in a half-babble, half-mutter. His speech sounded rehearsed, almost like a lecture.
"The tales say Astras was the hero of the Fellowship – not so, not so. It was one of us, the gnome, the mage, that solved the ultimate paradox."
"Sylvanas was furious that his tenets had been ignored, that the intelligent races were taking up arms and tearing down all of creation in the service of war. He drew upon the Green Dream, the ethereal stuff of the universe, to create the Tarrasque, the most unimaginable horror that ever was; the enemy to all living things, to nourish it, enervate it, encourage it on. But Naraoch, the sole being that had lived long enough to have seen Sylvanas do this before at the creation of the dwarves, was ready – and sought to deceive the Fellowship, and use the opportunity to swim upstream wherever it flowed into our reality, to find out what was on the other side of the Green Dream, and to seize that reality - what she thought was the true reality - for her own. Do you see the paradox Bo Blackchin faced?"
The women looked at one another. Who was he talking to? Without an answer, he continued to ramble. Vega was resolved -- he must be a tutor or professor of some kind, going off on a prepared speech. His words were clearly memorized, but delivered flatly, airily, without any thought to whether he was being understood.
"He could not close the channels of the Green Dream, or all life on Oa would dry up and die," he continued. "He could not allow them to flow, or the Tarrasque would be nourished and return to its omnicide. He had to devise some artifact that would allow just a glint of the Green Dream, just enough, to pass through like light; and he also, somehow, had to restrain the arch-lich as she sought to pass through the other way."
"So here was his genius: at the moment she entered the flow, Archmage Bo’s fellow mages, spread across the globe, stood ready, reached in with their arcanum and caught her howsoever they could – arms, legs, by her hair. And that is where the famous image of Astras comes in; he does not drain her blood in combat; that’s ridiculous. She would have flattened him with a thought. But overwhelmed in the moment of defying divine creation, disoriented by being pulled into reality piecemeal, she is held tight by strong magicks across Oa, existing everywhere at once in a different plane of reality but being pulled out into our single, linear reality in six places at once. And in the moment he has, Astras opens her neck and exsanguinates her. The ancient magic flowing through her veins was too strong for her to be held by any mortal contraption for long. So it was drained away, and it floats loose in the Green Dream still. And each coterie of wizards snapped shut their Lanterns on the cursed limb in their possession, blood, aether and all."
"She does not have the strength to make herself whole once again. But those in her thrall needed only to open the Lanterns to allow the Green Dream to flow, to waken the Tarrasque, to allow her to regain strength, to claw her way back out."
Fanny was fully checked out at this point. Cherry frowned at him in concern. Beulah was struggling to keep up, and Vega's eyes were wide. She desperately wished she had a notebook, storing away as much of this rambling as she could manage.
"How could he be sure that would never happen? He was only a mortal gnome, though truly the greatest and wisest among us. What magic could he devise that would stand against any force at any time in the future?"
"Ah, the elegance! The simplicity! His masterpiece. He didn’t make it strong. He made it weak, enchanted the glass to bend, to be pressurized into a vacuum by the arcane force of her blood. Only an equal amount of force - the force of her life’s blood - on the outside, in this reality - could equalize the pressure and allow the Lantern to be opened."
Cherry began to worry that maybe he should just be resting. His words were starting to slur.
"But in this reality, she exists in six places! We gnomes always answer a question with a question. He answered the unsolveable riddle with an unsolveable riddle of his own - even if you had a phylactery of her blood, a whole life’s worth, you could only open one! How can you spill life’s blood, six times over? It’s impossible."
"That’s where you come in, my dear." Fanny's attention raised up from her fingernails. Two of them had chipped, but this seemed important too. "Naraoch was a lich. Paranoid, cunning, consumed by her affinity with blood magic. What the Fellowship did not know, could not have known, was that centuries before the war, she created a living phylactery - a child - a vessel for her essence that would go on unknown even to her own worshippers. A source of power, free from any possibility of betrayal."
"That essence flowed, transferring from generation to generation, through unknowing vessels. And if the enchantment on that spyglass identified you… then you are that vessel, your blood is hers. They sought to test it here, but the attempt was desperate. Even if it had worked, if by your life this Lantern opened, they could not open the rest. Perhaps they thought they could make progress with just one limb, with this fraction of her blood."
"But all for naught," he sighed, opening his eyes once more and finally speaking to the assembled women rather than lecturing loosely into the air. "I thank you, all, for your bravery. You have brought an end to the greatest of evils. And Clytemnestra, you are with us now. You will come with us, to Anthur-Ro. You will be safe there. The Orders, at last, are free to return to the surface. And in many years’ time, when you pass, Anthur-Ro will be boarded up, the Necropolis will cease its eternal labour. Praise to the Goddess, Naraoch’s last living heir is found. And when your line ends, so ends the nightmare of all creation.”
A long, guilty pause followed. Beulah broke first, chuckling despite herself. Vega smiled and shook her head ruefully. Cherry buried her head in her hands.
"Uhhh," droned Fanny, for once stuck for words.
"Your line?" asked Beulah. "Oh, maid--" she broke into fitful laughter and Vega followed, covering her mouth.
"Uhhhhh--"
Cherry snickered and fell into the paroxysms of laughter shaking the three of them together.
“What?” asked the gnome.
"What's so funny?"