Here is what is known so far.
The Gray Mist was born in the fissure between two universes, and therefore, it does not belong to any single universe.
Furthermore, it seems to have an intricate connection to the Swarm King's appearance in the Ultra Universe.
But... why the Swarm King specifically?
It's well known that among the many Aeons, the Swarm King's power is middling at best—outclassed by the greats, but a cut above the rest.
Compared to a great divine being like IX of The Nihility, the Swarm King is less than an ant. Yet, compared to younger, less powerful Aeons like Nanook of Destruction, the Swarm King's destructive power and intimidating presence are a step above.
Therefore, it's hard to imagine what the purpose of the Gray Mist is. Or perhaps it has no purpose at all, and it simply chose the Swarm King because it's mindless?
If that's the case, there are plenty of mindless monsters in the Ultra Universe, some of whom are incredibly powerful. Why haven't they appeared in the Honkai: Star Rail universe?
Or have they already appeared, but their destructive and catastrophic potential paled in comparison to the Swarm King's, so they were simply never shown on screen?
---o---
Light Curtain Bullet Chat
The Bishop of Destiny: "The Swarm, Hyper Zetton... the Swarm King has lost everything. He no longer possesses the ability to fight Ultraman Saga. The only thing to be wary of... is the Gray Mist that has been present from the very beginning."
"Ace Pilot of the Death Squad": "The Gray Mist... For humanity, the unknown is always the most terrifying thing. But with the Ultra Warriors present, even the greatest disaster will be overcome."
Although Shinjo had never met any Ultra other than Tiga in his life, after watching the light curtain for the third time, he had to admit that the Ultras were a flawless race.
Whether in personality or ability, the Ultra Warriors were the ideal that humanity aspired to. Perhaps that was why some people revered them as gods.
The Uchiha Dancer: "Because the Ultra Warriors are here, the Gray Mist isn't a problem? Foolish. If even Ultraman Noa finds it troublesome, could it really be that simple? Even with Ultraman Saga and Ultraman Reiga added to the mix, I doubt they can solve that mass of gas."
Elysia: "Relax, we don't even know what its true form is yet, do we? We should have faith in them. After all, the light curtain has been singing the praises of love and peace from the very beginning, hasn't it?"
---o---
[On the light curtain, time passed, second by second.]
Two legendary-class Ultra Warriors pursuing the same enemy—it had to be said, the Swarm King was getting a lot of attention.
However... Ultraman Reiga was one thing, but trying to escape from Ultraman Saga, whose mastery of spacetime was so profound that his instant movements had no cooldown, was truly asking for the impossible.
Somewhere in the cosmos, Tayzzyronth, the Swarm King, gave up the struggle, staring blankly at the brilliant figure before it.
The light emanating from Ultraman Saga made it a little dizzy. It had to be said... sometimes, the light of an Ultraman could cause a fair bit of light pollution, and the stronger the Ultra, the worse it was.
"There is nowhere left to run. Surrender," the majestic voice rang out. Ultraman Saga struck a ready stance, the indicator on his chest glowing with a seven-colored light.
In the next moment, the Swarm King reacted. It felt the changes in the surrounding space, and its expression gradually grew grim.
Sealed.
Ultraman Saga had sealed the entire region, spanning several hundred light-years. Unless it could defeat Saga in the domain of spatial power, it would be trapped in this patch of space forever.
But... could it possibly be stronger than Ultraman Saga in spatial manipulation?
Among all the Ultra Warriors, only Noa would dare guarantee he could best Saga in spacetime abilities. The rest were not quite up to the task.
Evidently, while the Swarm King was unrivaled on the Path of Propagation, its attainments in spatial power were, if not nonexistent, pitifully small.
Although some of its progeny, like the space-faring insects, could tear through space and traverse dimensions, it was obvious that even all of them combined could not hope to overcome Saga's spatial power.
A seven-colored light appeared around Saga's body. An azure vortex materialized, and in an instant, Saga vanished from his spot and reappeared behind the Swarm King.
With a single chop, a dull thud echoed from the Swarm King's body.
"...!"
A piercing screech rang out again. The wide-area AoE damage forced Saga to continuously teleport.
Azure flashes of light flickered through the air as Ultraman Saga, relying solely on his spatial abilities, dodged the sonic attack.
While evading, Saga gathered the energy from the bracelet on his wrist.
In mid-air, several spheres of light, under Ultraman Saga's control, assailed the Swarm King's body from all directions.
"Boom! Boom! Boom!!"
Within Saga's domain, the Swarm King had no ability to dodge whatsoever and could only take the attacks head-on.
But... even so, as long as its concept and essence as an Aeon remained unchanged, the Swarm King was an eternally immortal and indestructible existence.
Although it could feel the searing pain and burning heat on its skin, these sensations did no physical damage to the Swarm King's body. They only served to enrage it.
Stretching out both its hands, the Swarm King's piercing screech rang out once more. This time, it wasn't for attack, but for propagation.
Its massive body began to twist and change, quickly forming dozens of clones, then hundreds of avatars. This was the splitting ability that the Swarm loved to use most in battle.
After fighting the Swarm for so long, Zero and the others were more or less completely familiar with the Swarm's combat habits and abilities.
Simply put, the Swarm had only one style of fighting: overwhelm with numbers. It was a racial trait, after all.
A pile of scattered sand, when brought together, can devour everything. Snowstorms and floods work on the same principle.
Though simple and mindless, this was the very reason the Swarm was invincible throughout the cosmos.
And as the Swarm King's split bodies, each of these insects possessed the individual combat power of an Ultimate Ultra, some even stronger.
"Seriously? It's still breeding at a time like this?" Stelle clutched her head, feeling dizzy at the sight. This was all it took. After coming to the Ultra Universe, she had been forced to develop both trypophobia and entomophobia.
"The Swarm King can use this trick too? Right... after all, it's the source of the entire Swarm." Musashi frowned and said. It was the same splitting ability, but the concept of the Swarm King and the Swarm Kings were completely different.
No matter how many times a Swarm King split, it was still just that. But the Swarm King was different. It had both numbers and strength. Even a being like Ultraman Saga, who symbolized miracles, found it extremely troublesome.
"Who cares! We've seen this kind of scene many times before! Before they can split even more, let's take them out!" Asuka clenched his fists. He was just that kind of impulsive person.
But the reality was just as he said. The best way to deal with this type of enemy was to wipe out all the split bodies at once. Otherwise, the insects would just regenerate endlessly.
---o---
In the infinite multiverse, logically speaking, the Swarm King's offensive methods were hardly fresh, as they had been seen before when fighting its other insects.
Although the process was a bit tedious, as long as Ultraman Saga wasn't one of those "I can't maintain this form for long" types of temporary fusions, then defeating the Swarm King was only a matter of time.
However, another point that piqued everyone's curiosity was... where was Ultraman Reiga? Didn't he follow them here? How come he was nowhere to be seen?
Yukino Yukinoshita: "His spatial abilities may be inferior to Saga's, but Reiga is still recognized by the light curtain as the strongest Ultimate Ultra. Why haven't we seen him after all this time?"
Utaha Kasumigaoka: "Don't tell me he actually got lost. That would be a huge embarrassment for the strongest Ultimate Ultra to his predecessors."
Outside the light curtain, many viewers began to complain. The main reason was that the New Generation Ultras hadn't had any particularly high-profile moments.
Although they were the ones holding back Hyper Zetton and the Swarm King before Ultraman Saga appeared, their battle record was essentially zero, aside from their contribution to the Swarm's defeat. They did get one assist, but many viewers refused to acknowledge it.
Ultraman Noa had gone through so much trouble, even risking a potential time paradox, to pull these New Generation heroes back. They shouldn't have been brought here just to land an assist.
Dr. Romani: "Ultraman Reiga, time travel, the Gray Mist... My head hurts. What in the world is the great god Noa thinking? The information gap between mortals and gods is just too vast!"
General of the Luofu, Jing Yuan: "It has the flavor of a riddle-maker. But in reality, Noa hasn't said a word up to this point. Perhaps the answer is simple, and Noa is just too lazy to explain, or he hasn't had the chance to tell us. Haven't you noticed that not a single Ultra Warrior has questioned Noa's actions?"
The Short Head of the Master Diviner Commission: "If we consider the Xianzhou as the Land of Light, then Noa and Ultraman King are the Reignbow Arbiter. Just as most people of the Xianzhou have unconditional faith in the Arbiter, so too do the Ultra Warriors."
The Bishop of Destiny: "Actually... I have a theory. Is it possible that for Noa, summoning Ultra Warriors from the future, or even the past, is not a difficult matter at all, and the so-called time paradox simply doesn't occur?"
---o---
[On the light curtain, with no time to worry about Ultraman Reiga's whereabouts, Ultraman Saga had been facing off against the Swarm King for a long time.]
Ultraman Saga was completely surrounded by the Swarm King's split bodies. At this point, instant movement was meaningless, because every direction was within the line of sight of a Swarm King. No matter which corner of the battlefield he teleported to, he couldn't deal with a Swarm King that was already prepared for him.
"Can't kill them all, just can't kill them all! And this is different from the regular Swarm. How does the Swarm King come with a self-healing buff?!"
Watching the Swarm King's split body she had just painstakingly defeated split once again, Stelle felt a wave of dizziness.
Oh no, her forced-upon entomophobia was about to act up again.
"Calm down. We're sure to find another weakness!" Musashi analyzed as calmly as ever. This time was different from before; they had enough time to wear the Swarm King down.
The energy of Ultraman Saga was very stable. As someone who had once transformed into the legendary Ultraman, Cosmos could feel it clearly.
Although the fusion partners had changed, Ultraman Saga was essentially similar to Ultraman Legend. As long as the fusion partners did not voluntarily exit or have their danger levels removed, he could maintain this state indefinitely.
And as long as the Swarm King was trapped here, the rest of the Swarm would lose their source of arrogant strength.
It was well known that the most terrifying reproductive capabilities belonged to the Swarm King and the Swarm Kings.
Now that the Swarm Kings were nearly extinct, and the remaining Swarm King was trapped here, the decline of the Swarm was only a matter of time.
"...!!"
As if ten thousand insects were chirping at once, the sound echoed again. The Swarm King wasn't stupid. Well... perhaps it was quite stupid, but even so, it could see Ultraman Saga's intentions.
Without the Swarm, the Path of Propagation had, in a sense, reached its end.
Several Amber Eras ago, the Aeon of Propagation was but one of many coleopteran swarms. But their race was slaughtered by the Self-Annihilators and bounty hunters.
As the one and only, the final coleopteran, it used loneliness as its kindling and the Path of Propagation as its flame, embarking on the road to godhood.
The actions of the Ultra Warriors today were no different from shrouding the Swarm King in loneliness once more, forcing it to experience the extinction of its race all over again.
And this... was a result the Swarm King could not accept.
But it was no match for Saga. All it could do was roar in impotent rage, venting its fury at the endless starry sky.
"...!!"
Its vibrating elytra swept across the battlefield like a storm. Tens of thousands of insect cries seemed to reverberate throughout the cosmos. The Swarm King, that symbol of an Aeon's Authority, seemed to merge with the entire universe in that instant.
In the distant horizon, something seemed to be born, to be emerging, to be expanding at a speed visible to the naked eye.
"What is that...?"
Insects? No, perhaps that wasn't the right word.
This was not simply an insect born from the Path of Propagation. It was a terror born from the Swarm King's desperate shrieks, a fear born as the Gray Mist spread to the edge of the universe.
It was not a living being, nor was it an insect. If one had to describe it, it was... a formless condensation.
Spanning tens of thousands of light-years, a terrifying energy descended upon the Aeon. At this moment, the Path of Propagation was completely ignited. The world known as the Ultra Universe, at this moment, gave birth to its own Path.
"What... what's happening?!"
It was too fast. All of this happened in an instant, so fast that even Ultraman Saga's teleportation couldn't possibly keep up.
At this moment, the split Swarm Kings began to merge into one, floating in the cosmos.
However, Ultraman Saga felt that a terrifying change had occurred in the Swarm King's body. It seemed to have... unleashed something.
---o---