After kicking the Three Crows halfway across the city, Ryuga didn't forget to reunite the rest of the trio with their red-scarfed comrade. Though they hadn't been defeated per se, they were in no shape to continue—especially with Stalk, the master manipulator, undoubtedly lurking nearby.
To Stalk, Ryuga was an anomaly—a man born from his own genetic design. It was expected that Ryuga would surpass the common rules of power. In fact, it would've been strange if he didn't.
"Hey!" Kazumi (Grease) shouted, chasing after Ryuga. The Hazard-enhanced Smash forms had a fail-safe: death upon defeat. No big brother would let his subordinates die under his watch.
As Ryuga disappeared down the street, Sento (War Rabbit) de-transformed with a heavy breath, only for Stalk to appear behind him in classic dramatic fashion.
"Sento, are you really going to let Ryuga fight alone?" Stalk's tone was thick with derision.
Sento gave him a tired look. What exactly do you think I can do?
The Forbidden Trigger
"Did you find the Build Booster notes Katsuragi left behind?" Stalk asked casually.
"Some of them," Sento muttered.
"Perfect. Then let me help you out." Stalk pulled a red device from his coat and tossed it to Sento. "The Hazard Trigger. Katsuragi's ultimate invention. Forbidden for good reason."
Sento turned the device in his hand. "What's the catch?"
"Massive power. But if your danger level isn't high enough…" Stalk's voice dropped, "You lose yourself. Total mental breakdown."
"Same thing the Three Crows used?"
"Exactly. They became HazardSmash with it. But because they're built from Smash material, once defeated—they're gone."
"Then why give it to me?" Sento narrowed his eyes.
"Because only you can stand beside Ryuga," Stalk said, for once, with unnerving honesty. "He's a natural. A warrior by birth. You… you're crafted. A man built by science and will."
"Two species evolving in parallel. That's the story I want to see."
"What does that have to do with your goals?"
"I'll tell you later. Ciao~"
And just like that, he vanished into the night, leaving the forbidden Trigger in Sento's grip and a storm of thoughts in his head.
Kazumi and the Three Crows were spared—again. Ryuga let them go. Something about them still felt… redeemable.
Back at the base, Sento poured over Katsuragi's data, Hazard Trigger beside him like a loaded weapon.
Ryuga climbed into bed without a word. He had been fighting non-stop. Smash. Mecha-Defenders. No time for rest, no time for K-dramas. Truly a low point in life.
"Ryuga… what happens if I lose control?" Sento asked, breaking the silence.
"I'll beat the sense back into you so hard, you'll forget Stalk ever existed," Ryuga mumbled into his pillow.
Sento blinked. And somehow… he felt better.
"Also, maybe you are the boss's kid. He sure dotes on you like one."
"Get out."
As battles raged across the city, Misora, while tending to Sento's wounds, inadvertently awakened a portion of Princess Mars's latent power—granting her miraculous healing abilities.
Moved by a vision, she and Sawa rushed to the hospital and, under Gentoku's secret orders, healed Prime Minister Taizan Himuro, who had been comatose for weeks.
Upon awakening, Taizan promptly dismissed Gentoku (Night Rogue) for his war-mongering and seized Pandora's Box in a rare moment of spine.
Gentoku fled with the Box—but was quickly intercepted and defeated by Sento, now resolved to end the war. Night Rogue was officially offline. When he returns, he'll be under a new name and suit—if he returns at all.
The Hazard Awakens
With Pandora's Box secure again, Sento raced to the battlefield where Ryuga was locked in a fierce one-vs-four against Grease and the Three Crows.
Seeing his friend pushed to the limit reignited something in him.
"If I want to stop this war, I need to go all in—even if it costs me everything..."
Sento pulled out the red Hazard Trigger and gritted his teeth.
[Hazard On!]
"Even if I lose my life... I'll stop this war!"
(Lan Yu: "Excuse me?")
[Rabbit! Tank!][Super Best Match!][Are you ready?]"Transform!"[Uncontrol Switch: Black Hazard!][YABEEEEE!!]
A shockwave exploded outward. The five men fighting froze, staring in awe.
From the haze emerged Kamen Rider Build Hazard Form—a black figure with a razor-sharp presence, radiating power and instability.
"So cool…" Ryuga whispered. "Definitely the coolest form he's got. Well, besides RabbitTank Sparkling. And the Twin Breakers. But this... this one's peak."
He paused. "Wait… is his waist thicker?"
"..." Had Sento not been struggling to control the hazard system, he might've punched him on the spot.
Still, he remained focused—stepping directly into the path of the Three Crows, who, empowered though they were, still lacked the intuition to realize they were outmatched.
Kazumi's eyes widened. "That's the Trigger…! Stalk said if they were enhanced by it, imagine what someone like Sento could become…"
He moved to intervene—but it was already too late.
Sento, in full Hazard form, blitzed through the battlefield, grabbing all three Crows and teleporting them somewhere unknown.
"Wait—what?!" Ryuga turned to Kazumi. "He can teleport now?! I thought that was only for bosses or final forms!"
"You think I know?!" Kazumi yelled back.
"You've got a helicopter bottle! Track them!"
Kazumi scrambled, trying to locate them. "If he loses control, the Crows are dead! He doesn't even know how to use that thing properly!"
"This isn't a game! That scene-switching trick doesn't work in real life!" Ryuga ranted. "He's not Kuroto Dan! He doesn't have a reality-breaking Rider System!"
All they could do was try to trace the signal… and hope.
Because at this moment, the war wasn't just about territory or Full Bottles anymore.
It was about control. And survival.