As Sougo stepped back, Eternal launched his final, full-powered Rider Kick directly into the alien world's dimensional space.
Crack… crack… crack…
White cracks burst across the surface of the alien world, spreading rapidly like lightning veins. In an instant, the entire realm was engulfed in blinding white light—shattering apart with a deafening boom.
In the real world, Owada and the others—used to construct that artificial dimension—were suddenly ejected from a collapsing dimensional wall. At the same time, Kamen Rider Zi-O Trinity's transformation dissolved, releasing Sougo, Gates, and Woz.
"This is..." Gates looked down at his hand in disbelief before turning his eyes toward Sougo.
Their gazes locked. The air between them grew heavy with tension.
Just then, Eternal—having landed back on the ground—stood up and canceled his transformation. He turned to Sougo with a bold grin.
"This wind... feels amazing!"
"I used your power," Sougo said earnestly. "I'm sorry."
"No need," Eternal chuckled. "Thanks to you, I destroyed the world that kept me resurrected and alone."
He raised a thumbs-up, his expression solemn.
"Now, I can finally return to my companions."
With that, Eternal's body began to dissolve into glowing fragments, carried away by the wind.
Elsewhere, the dark steam Minato Miharu had been facing dissipated into silence.
"You've managed to destroy one of them," Swartz said coldly, stepping forward with a scowl. "But don't think you've wiped out all the alien worlds."
Suddenly, the Dimensional Wall shimmered again, and the four villainous Riders previously summoned reappeared.
"Gates, let's go!" Woz shouted.
He and Gates immediately charged at the enemy Riders, drawing them away and leaving Sougo face-to-face with Swartz.
"You're alone now, Tokigawa Sougo," Swartz said, hands in his pockets. "Let's end this."
"I'm not alone," Sougo answered firmly.
"Miharu!" Swartz turned just in time to see Minato Miharu leaping toward him—screaming his attack. He sighed.
"Really? You're yelling during a sneak attack?"
Without looking back, he flicked his hand dismissively.
"Didn't quite catch that," he said.
Time froze.
Sougo was suspended, powerless to move. Minato Miharu, who had been mid-air, suddenly lost his momentum and dropped to the ground like a puppet with cut strings.
"...I said I'm not alone. I am a king," Sougo declared, once released from time.
Good thing I expected that rookie move wouldn't land, he thought.
"You really are a true king," Swartz said, almost admiringly.
"Become king, save this fractured world—that is your destiny."
At last, the face of the dark figure from Sougo's dreams—the one who'd always told him to become king—was revealed. It was Swartz all along.
Though he'd heard it before from Ryuga and others, seeing it with his own eyes finally made it real.
"I've been watching over you all this time. You've grown... into the perfect king," Swartz continued.
"Why?" Sougo asked, expression darkening.
"To gather the power of all Riders," Swartz replied with a cruel smile. "So, I can take it from you."
"This was all so I could become king."
"You're not fit to be king," Sougo said coldly.
"Oh? But I already have the power to rule this world."
"A true king brings hope and change," Sougo retorted.
"Sorry—that sounds more like a scientist than a king," Swartz laughed maniacally. "But if you want to stop me... then defeat me!"
"I've always intended to!"
Sougo immediately transformed into his Grand Zi-O form and launched a direct punch.
But Swartz, now transformed into a monstrous version of Kamen Rider Decade, blocked it with ease.
"Before you get too excited," he said, deflecting the attack, "you should know something."
"If you defeat me, then this world—my world—will vanish. That includes Tsukuyomi as well."
"What?!" Sougo's expression froze. His attack halted.
"We cannot coexist in the same time and space. Just as I cannot stand beside you, neither can Tsukuyomi remain if you destroy me."
Swartz paused.
"I'm not attacking now because I want the true power of the Demon King—not this downgraded version."
"There's only one way to resolve this."
"What is it? Tell me!" Sougo demanded.
"Don't believe him!" Minato Miharu shouted, rising from the ground and rushing over. "He's trying to trick you!"
Swartz turned toward him, sneering.
A new Dimensional Wall appeared behind him. With a swift step, he moved through it and reappeared right behind her.
"Fool."
He delivered a devastating kick to his chest, unleashing a violent energy wave that sent Sougo flying, knocking him out of his transformation.
Grand Zi-O was defeated in a single strike.
Thrown back, Sougo hit the ground hard, tumbling until he reached Miharu's side.
"Miharu! Hang on!"
He opened his mouth as if to speak, but her body went limp. Lifeless.
Sougo clenched his fists.
This moment teaches us two painful truths.
First: Grand Zi-O, despite being a final form, was utterly overpowered. The Demon King's true power still lies beyond.
Second: Kamen Rider Aqua—Minato Miharu—faced his fate protecting the future, even if it cost him everything.
"Tokigawa Sougo," Swartz said coldly, ignoring the emotions before him, "you have three choices now."
"Choose Tsukuyomi. Choose yourself. Or… choose to become the King of All Demons."
"You must choose. Time is running out."
"What do you mean?" Sougo demanded, but Swartz was already gone.
Suddenly, the ground rumbled violently. Towering steel walls rose from the earth—walls so high they vanished into the sky.
With them came hordes of mechanical creatures and armored sentries.
The Sky Wall. Smash. Guardian Defense Units.
Somewhere, a familiar voice groaned:
"I spent a whole year tearing that wall down…"
Realizing the threat, Sougo rushed back toward the Five Halls of Kyuuya.
As for Miharu's body...
"I'm sorry... please rest here," he whispered before running.
"You're back!" Woz called out as Sougo burst in.
Sougo ran to the storage pedestal and stared at the Ridewatches.
"...Just as I thought."
"The Build Ridewatch?" Gates asked.
He looked over and noticed that the red and blue Build Ridewatch had turned grey—its power faded.
"The Sky Wall outside... it must be tied to Build's world. I remember seeing it when I visited in 2017," Sougo said grimly.
"That wall once divided Japan into three sectors," Ryuga explained, appearing from a time-space gate with Aura in tow. "Build spent a year destroying it... and now it's back."
"If he still remembers this, he might actually lose his mind," Ryuga chuckled darkly.
"Ryuga—do you know why Swartz wants to be king?" Sougo asked urgently.
"He's driven by ambition, mostly. Everything else is just an excuse."
"If you really want to know, ask Tsukasa to take you to where Tsukuyomi was taken. He probably brought her back there."
"You can't take us yourself?" Tsukuyomi asked.
"No," Ryuga said seriously. "I can travel through space-time, but I don't know exactly where you are in the multiverse. It's better to go with Tsukasa."