Only Yuuji truly pushes the fusion mode to an extreme level in the entire universe. The Heavy Particle Mode developed by Kyuub is essentially the same as nuclear fusion, which controls micro-particles to collide to obtain a brief yet unimaginably immense amount of energy.
Not seeking to last forever, only a burst of fleeting brilliance.
Yuuji, having mastered nuclear fusion and the Heavy Particle Mode, combines the power systems of two universes. Naturally, his displayed strength surpasses that of King Ghidorah.
More importantly, Yuuji has tread across countless timelines, wielding reality and illusion, and possesses the mighty power to suppress space.
Even King Ghidorah finds it futile despite its efforts to find and devour monsters during this period. Even though it resides in a high-dimensional realm and can surpass conventional time like Yuuji, it proves pointless.
Yuuji has never slowed his pace; there's no reason he would be inferior to King Ghidorah.
The terrifying orb that shrouded everything begins to crumble under Yuuji's relentless assault.
Crack!
Yuuji rips off one of King Ghidorah's massive heads.
The remaining two heads emit piercing screams, displaying their agony.
King Ghidorah becomes desperate, disregarding defense and focusing solely on using all its power to kill this insignificant human before it.
But Yuuji, resembling an actual god, seems to have lost his specific form; he embodies energy and rules, effortlessly maneuvering and flexibly appearing before King Ghidorah.
Snap!
One head is abruptly twisted.
Yuuji strikes continuously, his moves simple yet powerful, delivering his most powerful attacks.
The fusion power, the bombardment of billions of particles, the interweaving of endless reality and illusion, seems as if all the matter and energy in the entire starry sky were taken away by Yuuji for fusion reactions, chasing after the momentary explosion that lands on King Ghidorah's head.
Snap!
Yuuji forcefully detonates another head.
The cost is that the glow emitted by Yuuji dims significantly.
Killing a universe-level god head-on is not easy.
Planet Godzilla, having fled far away, now rushes back, biting off the previously torn head and greedily devouring it.
It finally finds an opportunity for a share.
Yuuji glances at it without concern.
Planet Godzilla, typically rigid-minded, has acquired some intelligence. After all, it's just a head, so let it eat.
But after swallowing the head whole, Planet Godzilla rushes back, aiming to attack King Ghidorah.
Yuuji restrains it with a hand.
"You're not needed right now; go do what you should do."
Yuuji opens a spatial gate with these words and tosses Planet Godzilla through it.
King Ghidorah then descends into utter madness.
That golden form, once transcending endless time and space, its supreme nobility and majesty, has now lost everything.
The only remaining head now widens its eyes. While enduring the pain, there was also a sense of deep disbelief.
Why is this happening?
It spent over a hundred million years climbing to the top of the universe, turning the entire universe into its vast hunting ground.
Time was its plaything, space its vassal, energy its servant.
All intelligent civilizations were merely pastures; all monsters were food for its periodic harvest.
Why did it end up where it is today?
When did this start? Oh, it seems to have started from Planet Godzilla. This guy fell into the black hole it temporarily created to come to Earth, and fell into the dimensional turbulence without a trace.
At that time, King Ghidorah lamented not having devoured Planet Godzilla because it was the most powerful and potential-filled monster King Ghidorah had ever seen. A mere twenty thousand years old monster, yet it has the entire star system within its attack range.
But no matter how great the potential is, that's all there is to it. All power is confined to the constraints of time and space rules, fundamentally unable to harm King Ghidorah who possesses spatial abilities.
A difference in evolutionary direction kept King Ghidorah confident in its absolute suppression over Planet Godzilla.
Who could have predicted it would turn out this way?
A mere human from another universe, now controlling Godzilla, gained the power of two universes, and hunted him down.
Just a human!
A frail human who could die with a mere breath! Why are humans so strong? How can they be so assertive? Aren't these numerous beings known for constructing various machines and relying on them for combat? Why are they so powerful individually?
King Ghidorah harbored intense resentment.
"If I also had the power system of another universe, I would far surpass you and kill you..."
King Ghidorah's last head finally sent out a thought.
This was the first complete sentence King Ghidorah had ever spoken. It had always disdained speaking with a human, simply killing and then eating them.
"You would still lose. You, an old thing who has lived for at least a hundred million years, have only grown to this extent. What's there to be proud of? I have lived for less than a thousand years and can kill you. If I lived a hundred million years, I would have long traversed multiple universes."
Yuuji was confident in this. He is not yet a thousand years old, so he is a standard; time flows in the normal space-time continuum.
Given time, he could ascend to a higher dimension and, after confirming coordinates, precisely deploy his clones across the universe.
Yuuji could ultimately surpass Ghidorah, mastering both time and space and existing at any spatial coordinate at any point in time.
Whatever Ghidorah could do now, he could do it too. What Ghidorah couldn't, he could also achieve! Not to mention, once mastering higher dimensions, conventional time becomes vague, possibly accelerating or decelerating the passage of time for the individual. Still, the growth rate would also change accordingly, which is relative.
Ghidorah remained silent.
"Such beings, humans..." Ghidorah muttered, still unwilling to admit defeat.
Damn it, a mere thousand-year-old insignificant human was about to achieve the ultimate victory.
Ghidorah exhausted its intellect but never imagined it would one day lose to a human.
If only it could replace Godzilla, enter that other universe, and master chakra, it would not have ended here.
"Time was still too short. I didn't get enough information from that human named Orochimaru..."
It also wanted to refine chakra, but without being in that universe and adapting to its rules to refine under those conditions, it was impossible to forcibly "create" such an energy system in the Monsterverse.
Even if it succeeded, it likely wouldn't be as valuable as its perpetual nuclear fusion.
"Chakra..."
Ghidorah was still full of rage and reluctance.
Yuuji stomped, crushing the massive dragon's head, "Forget it. Even if you had chakra, what could you do? Chakra is essentially about the manipulation of energy. Can that energy be greater than what you produce yourself?"
Ghidorah grimaced in a final struggle, its body beginning to emit a golden glow, using the last of its power to make the final explosion.
"I don't believe it! If I had chakra, I would be stronger than you, a weak human!"
In the Monsterverse, monsters are uniquely privileged, and Ghidorah is born sacred. He was born with space ability and has the conditions to go to other planets to devour monsters, so he quickly takes off.
Ghidorah thought, if a weak human could achieve such feats, how could it not?
"Indeed, because you started so high, you believe your future will be greater... But there's something you may not know, whether it's you, Godzilla, or another universe with chakra; I am different from all of you..."
Yuuji sneered, "Because I come from a third universe, distinct from all of you!"
"I can perfectly harness the power of your two universes, but you can't!"
Yuuji's body again burst out with a shimmering force that lit up the entire universe, launching a final fatal blow on Ghidorah.
"The third universe..."
This time, Ghidorah seemed to understand where it was lost and glared, trying to engulf Yuuji with its explosion.
The final struggle of the universe-level god brews the ultimate terror that will destroy everything. Time, space, matter, and energy are all heading towards the end of destruction.
At this point, Yuuji also used the last of his power.
He opened a space gate again, using his might to construct a spatial tunnel, pulling Planet Godzilla back.
This time, Planet Godzilla brought back another monster.
In a deep sleep on Earth, evading Ghidorah's search... Mothra!
"Not bad, you finally used your brain for once. Since it's the last struggle, we might join forces one last time."
Planet Godzilla roared in response.
Mothra, not entirely understanding the situation but vaguely knowing what to do, spread its wings, the dazzling light points sprinkling warmth into the dark, icy darkness.
Yuuji absorbed Planet Godzilla into his body again.
Facing the frenzied Ghidorah.
Yuuji clapped his hands, finally activating his strongest and also last-resort mode.
Godzilla Guren Mode!
Yuuji's body suddenly expanded.
Endless red lines, like magma, began to appear densely on his body.
Planet Godzilla inside the body enters the Guren Mode, increasing his energy index at an exaggerated rate, but the price is that his body is on the verge of collapse.
Guren mode is a form in which Godzilla overloads his energy, risking bodily explosion at the critical point to deliver the most potent attack.
For most Godzillas, entering this mode means the best outcome is mutual destruction.
Same as the Heavy Particle Mode.
But Planet Godzilla is one of the few who could survive this mode.
Hum! Buzz!
Under Mothra's guidance, the Guren Mode transmitted from Planet Godzilla to Yuuji.
Yuuji combined the Heavy Particle Mode and Guren Mode on himself; not only was his body collapsing, but every cell was screaming in agony.
His soul also began to falter under the strain of guiding and controlling this ever-escalating power until self-destruction.
But at this point, Yuuji didn't care anymore, he just wanted to have a final confrontation with the frenzied universe-level god in front of him.
"Mothra, you're no longer needed; return where you belong."
Yuuji pointed at Mothra, sending it back to Earth.
Boom, boom, boom!
This intensified confrontation far exceeded the past, devouring all cognition, transcending space-time limits, and existing only in profound nothingness.
It seemed like eons passed, perhaps a moment, or perhaps, at this moment, time had no meaning.
The universe suffered tremendous wounds; space flow drastically changed, destined to cause havoc for hundreds of millions of years.
But when all settled, Ghidorah was left with only one head, and its remaining consciousness was fading.
Yuuji stood awkwardly in place, his body battered but quickly healing.
Amusingly, physical damage is what he is least afraid of. No matter how many times, it can be easily repaired.
However, his soul had suffered significant damage, battered and needing a long time to recover.
"Rest in peace; I will receive your inheritance and take away everything you have in this universe."
Yuuji wobbled over to Ghidorah.
Only one head was left.
"I never asked your name before... Tell me, human." Ghidorah's mouth opened, its eyes gradually losing light.
"Yuuji."
"But Orochimaru said you're also called Shiranui."
"That, well, that's in the past, just a transitional identity code."
"Hmph, how casual..."
Ghidorah's consciousness wholly dissipated.
Yuuji raised his hand, and countless pieces of flesh grew from his body, covering and devouring the massive dragon head before him.
Yuuji also seized Ghidorah's genes.
What he will definitely get is Ghidorah's right to rule the universe.
"It's over."
Yuuji let out a long sigh as if personally putting a full stop to this battle.
"It's over, exactly as I expected."
Kabuto and others had used their spatial abilities to hide far away early, and only after sensing the fluctuations gradually calming down did they struggle to return.
Space was massively fractured but slowly repairing, making it very difficult for Kabuto and others to move.
"What do you mean 'as you expected'? This is the inevitable outcome," Kazue snorted.
Kabuto maintained his smile, not arguing.
"So, you're satisfied seeing the ending you wanted to see?" Kabutoi turned to look at the frail human by his side.
Haruo stared ahead, already lifeless.
"…He's already dead. Ordinary people can't withstand such an impact, especially since he was so old. For an ordinary person, this is a glorious death," Kazue glanced briefly, quickly losing interest.
She couldn't understand why Yuuji and Kabuto were interested in such an old man.
A hero from Earth? It was nothing special.
Kabuto shook his head, accustomed to Kazue's brashness and bluntness, and closed Haruo's eyes.
Swoosh!
Yuuji appeared beside them.
"Haruo... is he dead?" Yuuji examined the old man.
A hero born from a civilization, though incredibly weak to them, but as the counterpart to Planet Godzilla, was indeed rare.
"I'll send you back to Earth; you can rest forever on your beloved home planet, undisturbed."
Yuuji, carrying Haruo's body, arrived at Earth.
…
Earth of this universe.
Planet Godzilla was also pulled from his body and dropped here; the big guy was in terrible shape, like a chewed-up mountain, staring blankly at the scene before him.
Instinct told it this was its place of origin; its mission was to protect it.
This entire planet resonated with Planet Godzilla.
"This planet gave birth to two remarkable beings; one is you, and the other is him. Originally, his fate was tragic; to prevent Ghidorah's second descent, he chose to launch a suicidal attack against you, ultimately dying under your atomic breath."
Yuuji observed everything before him.
Whether Godzilla, Mothra, or the now-deceased Haruo.
These three were supposed to be the sons of destiny for this planet, just like the beings in the ninja world gave birth to Hagoromo and Hamura through Kaguya in order to change their own destiny.
Everything starts here and ends here.