The sound of motorcycle driving fast was music to Kamen Rider Decade's ear; even more so than the screaming and grunting of all the monsters he trampling was and driving over. He reached into his waist and grabbed his gun/sword, the Ride Booker, and proceeded to shoot the Fangires in his path. There was a new crisis in the Rider Multiverse, a legion of Fangires were taking over various worlds; it was only a matter of time before they would reach the prime Rider World and Decade wasn't one to take the chance. He still couldn't believe the amount of monster there was, if his sources were right, they'd be able to fill not one but two entire earths. If his sources prove to further be true, then he knows who their leader is, which is why he didn't bring a certain Rider with him.

Another Fangire jumped down from a ledge to take down the Rider, but Decade shot him midway, landing on top of his comrades. He took a glance at the predicament and couldn't help but laughed, this was a good job sometimes. Unfortunately, he didn't see the platoon of Prawn Fangires standing in his way releasing shots of explosive foam. Decade finally looked forward, 'Ah, shit…' he thought as the foam sped up towards him. To his luck, a large stone wall emerged from the ground and took the shots head on. Missiles launched overhead as Decade looked above ad heard explosions from beyond the wall as well as screams of pain and glass shattering.

Decade looked behind him, and there stood Kamen Rider Wizard in his Land Style and Kamen Rider Fourze with the launcher module on his leg. "About time you guys caught up." Decade jested as he got off his bike and approached the two. Wizard returned to his base form, Flame Style, and Fourze de-materialized his module. "Sorry about that, Tsukasa." Fourze admitted. "Not everyone can go as fast as you, old man." Wizard added, getting an eye roll from Decade, though he couldn't see it since their helmets covered their entire faces. "Sure, whatever. Where's the rest of the team?" Decade asked. Neither could answer as more Fangire showed up. "There they are!" one yelled. Before the Fangire could strike down, a foot landed on him along a hailstorm of bullets. Looking up, Decade saw Kamen Rider Build in his HawkGatling form along with Ex-Aid.

"The newbies aren't bad." Wizard commented, earning a nod from both his Riders. Ex-Aid and Build, who returned to his RabbitTank form, went down to them. "I'm not much of a newbie now, though. I should say I'm nearly on par with all of you." Build replied. Ex-Aid wrapped an arm around Build and chuckled. "Sento's every bit strong as we are; he's well earned his spot as one of us veterans." Build reached his hand out for a fist bump which Ex-Aid returned.

"Where're the others?" Decade asked, wanting to end the buddy moment to get his plans moving. Build pointed behind him and as Decade turned, his eyes widened in bewilderment as a car, the Tridoron if he recalled, started to run over and tackle Fangires; someone else had the same idea as him it seems. He could see Kamen Rider Ghost sticking his head out and shooting Fangires with his gun, it was like a scene straight out of an action movie. The weirdness just kept going as he saw more Fangires being shot and kicked by, what Decade can only describe as, a Kangaroo-Turret being ridden by Kamen Rider Gaim. A large platoon of Flying Fangires flew overhead and surrounded the Tridoron. Ghost put his head back in and the car started to drive donuts on the Fangires, taking them down with ease. The Tridoron stopped in front of the Riders and leaving the driver seat was Kamen Rider Drive, and leaving the front passenger seat dizzily was Ghost. He spun around, only barely missing the hood of the car. "Tomari, did you have to be so wild?" he asked. "Sorry, Takeru. Had to do something, though" Drive replied, patting Ghost on his shoulder. Gaim landed nearby and the Kangaroo-Turret thing returned to a simple lock with a tulip designed. "What is that thing?" Decade asked him pointing at the Lockseed. "Oh, it's called the Tulip Hopper." He answered, Decade made a mental note to go look for that one day; even he can see it's versatile despite its weirdness.

"Hey, look!" Fourze yelled pointing in another direction. The Riders looked over and saw a truck, the RevolGarry also running over Fangires, Decade wondered if it was a popular trend lately. He also saw an entire line of Kamen Rider OOO, all in GataKiriBa form attacking and pushing back dozens upon dozens of Fangires. The truck and OOO stopped in front of them, the truck opened up and inside was Kamen Rider W (Double), the OOO clones returned to a singular being and turned back into TaToBa Combo. "And that's everyone." Decade said, he hopped on back to his bike as he turned back to his Riders. "The path should be clear enough for us to head to the castle. We go in and kill their leader." He explained which they nodded to, they all got into their respective bikes, including Ghost who didn't want to take a risk riding with Drive. "Will killing their boss do that much damage to them?" Fourze asked. "The Fangires have a monarchy system," W explained, his right eye lighting up meaning his other half was talking. "They'll be in disarray due to them losing their leader, we can bring the others to strike back amidst the chaos."
"Speaking of the others…" Build started.
"If my research is correct, there's a Rider who fought the Fangires, isn't there? Why isn't he here?" Everyone else stared at Decade who was looking away. Finally, after moments of silence, he replied. "Bad idea. If he knew who the leader is, he'd hold back." The other Riders looked at each other and made a silent agreement to not pry; Decade kept secrets a lot and almost always it was for good reasons.

Decade had gone to them in their homes one by one, telling them of the crisis at hand. Surprisingly, he already made a plan on how to deal with the Fangires by taking out their leader. For some reason, though, Decade never told them who their leader is and they were as shock to learn one certain Rider wasn't going with them, nor did Decade plan to bring him once they brought the other Riders with them. Still, they knew Decade earned his place as one of the leaders of the Kamen Riders. He can have as many secrets as he needs.

The Riders made their way to the castle, riding through the empty fields that were once a world brimming with life. But now, all the lies now are ruins and decaying plant life. The Rider knew there had to be humans somewhere, the other half of W, Phillip, said that Humans are used as life source for the Fangires; the king in their world had called the humans cattle at one point. Sadly, they knew not where the humans are staying. 'One problem at a time' Decade thought. Finally, after a long ride, they finally made it to the castle. It's styled after European Castles, a large wall covering the main castle which had four spires, two were short, there was one that was taller than those two, but one practically eclipsed them in height. "At least they're keeping up with the theme." OOO said as they drove in to the castle. The Rides hopped off and entered the castle with caution. As they opened the door, however, there was no guard in sight and instead the place was empty and dark. The torches then lit up illuminating the hall, the Riders readied their weapons and proceeded onwards.

"So, these guys are essential vampires, right?" Fourze asked gaining the attention of Build. "According to what I've researched, they're like vampires but not entirely. Instead of drinking blood they suck up, and I'm quoting what I've read, the life energy of humans. God knows what that is."
"Probably some sort of magic." Wizard interjected.
"Man, first the Witches and now I have to deal with vampires?" Fourze commented, Wizard looked back with his head tilted.
"Witches?" he asked. "Were they Gates?" Fourze shook his head. "No, they were using Cosmic energy to make it look like they had magic."

"I must look into this 'Cosmic Energy' one day, it seems interesting." Build said, he turned his head towards Wizard. "Though, first I should look into your 'Magic'. I will find the source." Wizard, in turn, shook his head in dismay. "I keep telling you, I don't know how to explain it. My Magic just happens, you can't find it in a radar."
"Impossible, there's nothing science can't explain."
"It's not science." Wizard retorted.
"Everything is science." Build countered. "And I'm a genius, I'm sure I would find it eventually." He added, earning an eye roll from Wizard.

In front, the other Riders were discussing a not so subtle conversation. "Sento really has a giant ego, doesn't he?" Drive commented. "As a scientist I can respect his abilities, but I can't say the same for his ego." His belt, Krim who Drive calls Mr. Belt, added. "He's a good guy, though. I can tell." Ghost replied. "We're not saying he isn't, just that his ego needs to be in check." Gaim said. "I can hear you, you know!" Build shouted, the other three jumped with a shock. W, meanwhile, became interested in their conversation. "Actually, Sento, science and magic co-existed with each other until science became the more dominate one." Phillip stated, his other half, Shotaro, silently wondered how that happened; he admitted that he and his partner both found magic more interesting. "Right, you can see the earth's history." Build replied. "Can you tell me how humanity was born, then?"
"A death match made by God with the human representative winning." Shotaro deadpanned.
"Ha. Very funny." Build said dryly, though he noticed everyone else weren't reacting much.
"You can't be serious."
"You can ask Blade, I asked him and according to him that's what happened." Ex-Aid said to him nonchalantly. "He's cynical but he's not bad once you get to know him." OOO added. Build shook his head in defeat, muttering about how the other worlds don't make sense; none of them could see the smoke coming out of Decade's head.

"Will you guys zip it!" he shouted, shocking the others. "Decade's right, we're in enemy territory." Shotaro explained. "If we talk too much we could catch someone's-"
"Attention?" a voice finished.

Turning to the front, they saw a man with long hair tied by a ponytail wearing a black priest attire standing on the top of stairs, standing with him was another man with long hair wearing a motorcycle jacket. "Bishop," Decade said to the man with a ponytail, "And Rook." he said to the man in the motorcycle jacket. "They're part of the Checkmate Four." Phillip added. "So they're one of the generals, then?" OOO asked, crouching to get ready for the inevitable fight. Decade looked past Bishop and Rook and saw a giant door behind them, the Throne Room he figured. "I'm guessing your boss is in there?" Decade asked pointing towards the door. "You'd be a fool if you think you can win." Bishop scoffed as stained glass patterns start to appear on his face as well as Rook's. The two became engulfed in blue flames, transforming into Fangires; the Swallowtail Fangire and the Lion Fangire. The two jumped down from the stairs and engaged the Riders in combat.

Bishop aimed for Decade, but he dodges the attack in the last second. Turning around, Bishop went for Decade again, only to be stopped by OOO, Wizard, Gaim, and Ghost; Bishop's sword locked in combat with all of theirs and they all push him back. Rook dashed forward to help Bishop, but he was stopped by a flurry of yellow blasts. He turned back to see W in a new form. "LUNA! TRIGGER!" instead of being half green and half black, W was now half yellow and half blue equipped with a gun. Ex-Aid, Drive, Fourze, and Build arrived next to him to back him up. "Keep them busy! I'm going after their boss!" Decade shouted as he ran past the Fangires. The remaining Riders brought their weapons up and engaged the Fangires as Decade ran in to the Throne room.

Decade kicked the door open and went inside. The room was as dark as the hall outside. Decade spun around with his Ride Booker in hand, taking every step with caution. The sound of fire lighting up from behind shocked Decade, he immediately turned around and saw two gigantic torches illuminating the room. There he saw a hooded figure sitting on the throne. "So, you must be the leader of the Fangires." Decade stated. "You didn't bring him?" the figure asked. "No, I've a bad feeling he wouldn't kill you." Decade reached for a card, "Unfortunately for you, I got the guts to take you out!" He inserted the card into his belt for an attack. "ATTACKRIDE, BLAST!" four holographic versions of his gun appeared around him and fired their shots. The Fangire, though, fired shots of their own from their hands deflecting the gun shots. Decade inserted another card and dashed towards the Fangire. "ATTACKRIDE, SLASH!" Decade's Ride Booker switched into its sword mode as Decade thrusted his sword at the Fangire. Using their arms and hands, they defended each of Decade's sword strikes.

Wanting to end the fight quickly, Decade decided to bring in the big guns. He took out his smartphone-like device, the K-Touch. He inserted a card into it and typed in the code. "KUUGA! AGITO! RYUKI! FAIZ! BLADE! HIBIKI! KABUTO! DEN-O! KIVA! FINAL KAMENRIDE, DECADE!" from a black and magenta color scheme, into a silver and black color scheme with Rider Cards placed on his chest and head, Decade Complete stood ready to fight. He ran in, sword at hand, send the Fangire a flurry of sword swings. The Fangire was quick, however, and kept blocking all the attacks as they fought. Decade then swung his sword down again and the Fangire prepared to block it, but they didn't realize it was just a feint as Decade thrusted his sword back and stabbed them with full might. The Fangire was launched backwards, falling and hitting the stairs before landing hard on the floor. Decade somersaulted to their location, landing behind them and then wheeling around just to strike them again following it with a kick. The Fangire started to stagger backwards, the fight was in the bag! He removed the K-Touch on his belt and tapped on the Kuuga icon. "KUUGA! KAMENRIDE, ULTIMATE!" the K-Touch blinked rapidly as the cards changed into Kuuga in his ultimate form. Standing next to Decade now was Kamen Rider Kuuga wearing a completely black armor with spikes sticking out from the shoulders. Decade grabbed another card and inserted it into his belt; the Kuuga clone was also mimicking his movements. "FINAL ATTACKRIDE, K-K-K-KUUGA!" Decade clenched his fist as purple flames started to engulf his fist, Kuuga's hand started to be engulfed in a yellow flame. Decade readied his fist and launched a punch to the Fangire, launching it backwards to the throne and leaving it in rubble.

Decade dropped his fist as the Kuuga clone disappeared. He readied his sword, knowing full well this battle was far from over. The ruins of the throne started to shift and a slab of rock was thrown aside. He quickly took a card and inserted it into the belt as his Ride Booker switched into gun mode. "FINAL ATTACKRIDE, D-D-D-DECADE" a line of large holographic Rider Cards appeared in front of Decade and aimed at the Fangire. Decade pulled the trigger and fired a large blast of energy at them. The blast didn't connect, though, and instead was intercepted by a torrent of dark fire. The clashing blasts resulted in a giant explosion, almost filling the room with smoke. usually became scared of his opponents, but this time he did. Under the hood, the Fangire's eyes turned into a glowing red, they raised their hand showing the back of it to Decade, there was a mark on their hand that glowed an ominous purple; six eyes connected in u-shaped line. Decade suddenly felt an overwhelming feeling of dread, causing him to take a few steps back and look up, meeting face-to-face with a shadowy figure with six eyes.

Outside of the Throne Room

The Riders continued their fight against Bishop and Rook. Despite how strong the Fangires are, their strengths were obviously eclipsed by the strength of nine Kamen Riders. "Let's finish this!" Ex-Aid shouted, he was in his Lv. 99 form holding his sword, the Gashacon Key Slasher. He removed the Gashat from his belt and proceeded to insert it into the sword, only to be interrupted by the sound of the door being slammed open. Decade flew past them landing on the floor with a loud thud. "Tsukasa!" Fourze called out, he and the others quickly went to his side. They turned him over as light shined from his body, the Rider back into regular Tsukasa Kadoya. "They beat him even in his Complete form." Gaim said in shock.

Footsteps echoed in the room, everyone looked at the opened door and standing there was the Fangire Tsukasa fought moments ago. Rook and Bishop immediately knelt down towards the Fangire. "Your majesty," Bishop said. "I deeply apologize we were defeated easily by these ple-" his leader put his hand up indicating him to be silent. A chill ran up the spines of the Riders all of a sudden. They then noticed a shadowy figure looming over the Fangire leader, a towering figure with six glowing red eyes. "We need to run." Tsukasa wheezed. Not wanting to take chances, the Riders quickly bolted to the door with Drive and Fourze carrying Tsukasa on their shoulders. "I give them five minutes." The leader commented.

The Riders made it outside the castle where Rider Machines were parked. Drive and Fourze split up as Drive entered the driver seat of the Tridoron and Fourze placed Tsukasa inside the front passenger seat. The Riders started their engines and left as fast as possible away from the castle. It was OOO who finally asked the million dollar question, "What was that thing?"
"I don't know, but its presence felt godlike." Gaim replied. "Damn, I haven't felt this terrified since Sonozaki." W commented.
"Was it a Dopant, then?" Ghost asked the Rider. W shook his head.
"Can't be, I looked into it and couldn't find anything that matches its description." Phillip said, Ghost noticed that the usually calm and collected Phillip had his voice trembling.

Wizard glanced at his mirror and noticed a lot of Fangires started to run towards them. "We got company, guys!" he shouted. Drive cursed to himself and turned to Tsukasa. "Can you make us a Dimension Wall to go through right now?" he asked. "Send us to my world, we'll be safer there." Build added. Tsukasa nodded slowly and lifted his hand, opening a small portal, but wide enough to fit all the Riders. The Riders revved up their engines and dashed into the portal one by one, leaving the world without a trace.

Meanwhile back at the castle

The leader turned back the Throne room; the Riders would have to be dealt with some other day. "Your grace," Bishop started, "I can't apologize enough for our mistake, please forgive us." Their leader turned to him and said, "No need to apologize further, Bishop. This one action won't heavily weigh your contributions to us." The leader turned around and headed back into the Throne Room. Bishop tried to speak up again, only he was interrupted by their leader. "Any new news?" they asked. Bishop relented and answered, "Yes. One of our scouts found another world, but this one is different. It's similar to the one where you gotten that power." That caught the leader's attention. They stared at the mark on their hand and turned to face Bishop. "Go on…" Bishop nodded. "Yes, your grace. The landscape of the world is the same, but from we have gathered the rulers are different, even the name of the continent has changed." Bishop smiled at the Fangire, knowing full well their intentions. "But the power, it seems, has yet to be claimed." The leader nodded back, "Thank you, Bishop. If there's anything I've learned in our conquest, it's that Kamen Riders are relentless. They'll probably be back with even more Riders. I need to depart at once!" Bishop and Rook were taken aback at that. "You shall go, your majesty? Are you sure?" Bishop asked. "Yes, that is the only way to ensure victory. No need to worry, you two will accompany me if you're worried about safety." The two men nodded back, though Bishop more reluctantly. A smile grew on the leader's face, soon their plans will be complete.

Unbeknownst to the Riders and the Fangires, however, there were three onlookers who witness the fight from afar. One bore a silver and red chest plate, a black skin-tight suit under it, a singular silver boot tied by chains, and a red and yellow visor shaped like bat wings. Standing next to him was a man also wearing a black skin-tight suit, white armor with blue trimmings, and a helmet that had gold cross on the face. Beside him was a shorter figure, she wore a dark purple cloak, somewhat tattered, with gold trimmings at the end of the sleeves, and her head was obscured by her hood. "Things are getting into motion, it seems." The man in white said, he turned around and left. "It seems like it." The woman in purple replied. "Things will go as planned, do you remember your place?" she asked to the man in silver. He nodded slowly, "I know, I just wish we can tell him." He felt his shoulder being touched, looking over, he saw the woman with her hand on his shoulder, beneath her hood he can see she was smiling softly. "Not yet, we will eventually. Remember, there's still so much we don't know ourselves." She replied. She turned and left too, leaving the man alone with his thoughts. "You'll know the truth," he said, as if there was someone he was talking to. "About why I came that day, and why we did what we did. But don't worry… dad. I will break the chains of fate."