"Attention Riders!" Tsumuri calls out to the Riders from the observation deck of the DGP. She talks through the monitors, four different screens, each displaying a different Kamen Rider. "We regret to inform you that the Jyamato has turned hostile. We apologize for this sudden transgression, as it wasn't in the plan for this ambush attack."
In every monitor, she sees the individual Riders reaching for their Spiderphones to hear her message more clearly.
"All Riders are permitted to defend yourselves against the Jyamato, and gain score. But the scores of other players will still be hidden as the original game still applies. If there is a Player Killer among you, sus them out to advance to the next game. Be strong, Riders. You have our blessing."
...
Fleeing the scene together, Élise and Yuto make like jewel thieves at a heist as they race down the mansion's drawn-out corridors, and hallways.
"Did you hear that?" Yuto calls out. "Seems like this wasn't planned. So now we've got a Player Killer, and a horde of killer mobs after us."
"About that," Élise replies. "I'm not too sure. Who do you think is the killer?"
"I already told you. Javier like you said. He was good with a sword, and we saw the markings on the walls. So it's him."
"But what if I'm wrong, and Alex was right? He knows Akihito more than either of us." Élise is conflicted. "Plus, Javier didn't do anything. He didn't defend himself, act offended, or anything. he just stood there, amused. Like he didn't think we were serious. Or he knows he's fine."
Yuto has a counter theory, "Okay then. What about Alex? HE found the scene, HE told us about it, HE was the first to point fingers, HE would have been able to attack John off-guard."
"But why would he do that? He and John had a good relationship. They way they spoke to each other like friends. I don't know anything about them. But I believe in them."
As they try to keep pace with each other, the mansion's interior starts shaking without warning. The shaking comes as a shock to both of them as the walls beside them start to crack. The cracks follow after them as if guided by another source.
Catching up with the two, the ceiling above them starts to cave in, and collapse on top of them both. Élise is quicker than Yuto, and leaps out of the way, dodging the falling debris, while Yuto is stuck on the other side.
"Yuto!" Élise gets up, horrified. "Yuto! Can you hear me?" The entirety of the corridor has been blocked off from both sides, meaning neither of them can join the other. Pushing the debris, Élise only barely sees through the mess of rubble, but can only make out bits and pieces of the other side before more of the walls and ceiling collapse down.
Élise does however make out a shadowy figure dashing past the falling mansion. Hearing the humming of the Jyamato, Élise isn't given the time to worry about Yuto and instead must focus on herself. Hand in her pocket, she grabs hold of the Magnum Buckle.
...
Akihito, transformed into Kamen Rider Scarlet has the time of his life. Using the Phoenix Buckle, he makes quick work of the now-hostile Jyamato. He takes the fight outside, taking on the countless stage Jyamato with his advanced utility. He turns the garden into a fire pit with the heat from his Buckle.
He has the time of his life. Keeping to the skies, he fires a barrage of burning feathers from his wings. They rain down like hellfire, laying waste onto the battlefield, racking up the points as he takes down Jyamato from afar, staying out of the range of their attacks. A few stray feather missiles soar around him, damaging some of the mansion's exterior. His carelessness and overkill deducted his points from his score, showing no respect for the level.
Scarlet can't help but laugh. He's having the time of his life.
"Boom! Burn! Fry! That's it, don't be shy!" He's over-confident as always. He swoops down, sprouting a pair of talon-like claws from his wrists. He twirls his arms around in an improvided motion, hacking and slashing the Jyamato as sparks bounce off of them before coming back up again.
"I don't know why you turned on us, but if I was your boss, you'd all be fired. Pun intended," he says as she creates a large ball of flames, and flings it over his shoulders at two Jyamato just joining the fight.
From nowhere, a cable with a hook attached to the end of it is fired from out of sight. Catching Scarlet off guard, it wraps around his body, and tightens, closing his wings. He's brought down from the sky as the cable retracts, dragging him down.
He struggles to move, trying to free himself with the talons, only for his arms to be pressed up together.
STRIKE!
From behind cover, the sword-wielding Rider fires a single stream of blue flames from their curved blade. Scarlet is struck in the back. He's let go by the cable and falls back to the ground. He tries to get back up while the rest of the Jyamato begin to crowd him.
Before he can defend himself, the damaged exterior of the mansion crumbles. A tower from the mansion breaks off from the building and falls. Distracted by the Jyamato, Scarlet only gets a second to see the tower crash down on top of him, taking out the surrounding Jyamato. The ambushing Rider retreats back into their hiding place.
...
Elsewhere in the mansion grounds, Élise engages a horde of Jyamato alone. Pulling the Magnum Buckle, she inserts it into her Driver.
SET!
She rushes for the horde, forgetting to pose as she triggers the Driver, "Henshin!" She transforms into Kamen Rider Snow, armed with the Magnum armor.
MAGNUM! READY, FIGHT!
The Magnum Shooter appears in her hand, and she gets to work using it on the horde. She takes aim as she charges the Jyamato. She opens fire on them. Sparks fly off their bodies before they drop like game NPCs.
More appear behind her. Turning on her heel, she accidentally activates one of the powers of the Buckle. An additional pair of wrist-mounted cannons flip open on her arms. Using all three barrels, she reduces the numbers to nothing. Her score keeps getting higher.
With the last of them defeated, she pulls out the Buckle from the Driver, disengaging the transformation. She takes a moment to breath. A lot has happened in such little time, and everything seems to escalate.
Taking another step, the wall beside her explodes with a Jyamato being tackled down by Kamen Rider Lure. Using their hammer Buckle, they take out the singular enemy before realizing they aren't alone.
Looking up, he smiles through his mask. "Élise!" They disengage the transformation. Yuto continues to smile, seeing a friendly face after going through so many Jyamato.
Élise reaches out and helps him back on his feet, "Yuto. I wasn't sure you survived the cave-in. Where did you go?"
"After we got separated, I tried to find you, or the others. I had to go back to where I came from and rounded back here. Lucky I did." Yuto clutches his arm, as he tries to stretch it.
"You okay?"
"Yeah. It's just that hammer needs a lot of energy to do anything to bring anything down with it."
"I see," she puts her hand on his shoulder as she guides him forward. "Come, we need to regroup with the others before more Jyamato can pop out of nowhere."
The two Riders make their leave, stepping over the defeated bodies of the Jyamato they just encountered. As they walk off, a third Rider watches them from afar. Stalking them, the Rider keeps out of sight to observe them. They remain hidden, with only a single ray of light revealing a faint hint of a blue helmet.