Raiden was going through the desperado headquarters, hunting down Sundowner when he got a message from Kevin on the Codec.
"Hey, Raiden, little heads up, but there's a guy in here hacking up Desperado cyborgs left and right. His blade isn't a high frequency, but it works better than yours seems to." Kevin informed him, showing him an image of a ninja in black leather slashing his way through each opponent that came at him, slicing pieces off of them with one slice.
"I see. So that's someone I'll have to look out for?" Raiden asked.
"From the look of it, yeah. My guess is he's either against Desperado like we are, or he hates cyborgs in general, if that's the case, watch your ass." He said.
"Got it." Raiden, said, then rounded the corner, encountering the very person he was just warned about as both took a step back and entered fighting stance.
"You're not with them, are you?" Ryu asked.
"No… And from what I've seen, neither are you." Raiden replied.
"Then who are you and why are you here?" Ryu asked.
"My name is Raiden. I'm here to take down the big boss Sundowner and get all the children's brains back." He said.
"My objective is the same. But, they're taking the children's brains?!" Ryu said, bewildered. He'd never heard of something that evil before.
"Yeah, they are. But I told you my name, who are you?" Raiden asked.
"I am Ryu Hayabusa." Ryu said.
"I see. One second." Raiden said, getting a call from Kevin.
"Raiden, I just realized who he was. That's Ryu Hayabusa! He's stopped global threats on 3 separate occasions and he's taking down things that would make you shit yourself! And it's said that his clan is descended from the dragon god, which is also what his katana is made of, the fang of the dragon god!" Kevin said.
"Wow, that special, huh? And I can't shit myself, anyway. Not in this cyborg body." Raiden said.
"Well, either way, you should see about getting him to help you. With the two of you working together, nothing could stop you." Kevin said.
"Okay then." Raiden said, hanging up. He then turned back to Ryu. "So, what would you say about working together on this?" He asked.
"It's always nice to have a helping hand, but… are you on par with me?" Ryu asked.
"Let's find out!" Raiden said, taking his stance, closing his visor.
Fight music: Headstrong by Trapt
The two of them ran at each other, but then Ryu jumped into the air and vanished in a flash out light, then appeared a few feet in front of Raiden, slashing at him, but Raiden blocked. At that moment, Ryu disappeared again and reappeared behind Raiden, grabbing him and impaling him through the stomach from behind. This would be fatal to most enemies, but Raiden is a cyborg with maxed out cyborg enhancements, it would take more than that to kill him. He pushed himself off the blade and ran at Ryu, slicing at him wildly, transitioning the sword from his hands to his feet, although Ryu managed to keep up with it. He countered and slashed Raiden across the chest, forcing him to jump back, then he pulled out the eclipse scythe.
Raiden tried, but he couldn't manage to get in close past the scythe, which Ryu swung with amazing speed and skill despite it being twice his size. Raiden then drew the pole-arm he got after killing Mistral (you can't say stole it if the owner is dead). This managed to catch Ryu off guard, as in addition to being a strong, firm staff, it could become a flimsy, unpredictable weapon. Once again, Ryu countered and swung the scythe with full force, slicing the weapon in half, as well as effortlessly throwing Raiden backwards.
"Gotta say, I'm impressed… But I haven't exactly started yet…" Raiden said, his voice now a menacing hiss as his body began to glow with an ominous red aura.
"What are you doing?!" Ryu asked, readying himself for another attack.
Suddenly, Raiden rushed forward, almost faster than Ryu could react, throwing deadly combos with immense strength, able to break Ryu's guard and sent him flying with a kick to the window section, almost sending him crashing through a window he crashed into. Raiden rushed forward and slashed, but at the last moment, Ryu vanished. Raiden looked around, but his cybernetics were better at tracking and analyzing cyborgs better than humans. Ryu came from behind and launched Raiden into the air. Ryu slashed him a few more times, then grabbed him spun in the air and smashed him into the ground, then jumped back. Of course, having taken far worse than that, he got up again, still raging as "Jack the Ripper". He hacked down at Ryu, who blocked it, but was easily forced onto one knee, unable to stand up to Raiden's strength. Raiden laughed evilly, but then realized what he was doing and came back to his senses, letting up a bit. Ryu took this moment of hesitation and pushed Raiden back, leaving him open, then kicking him in the side, sending him back, unfortunately waking The Ripper once again.
Ryu threw dozens of shurikens and shot at Raiden with his bow and howling cannon. While Raiden was able to easily block the shurikens and even slice through the arrow, his reaction time in his damaged state wasn't fast enough to allow him to dodge the cannon ball from the rifle-cannon hybrid. It blasted him back into a wall, but he was more than capable of going. "Let's see how this works!" Ryu said, using the Art of Inazuma, blasting Raiden with massive electricity, frying some of his circuits, still leaving him being somewhat operational, but he could no longer use his "Jack the Ripper" thing.
"What, the?! Kevin, Dok, what the hell is he?!" Raiden asked, bringing both of them up on the codec.
"Well, hard to say. He's obviously not a cyborg, but no human should be able to do that…" Doktor said, incredibly nervous and confused.
"It's called Ninpo. A few people, mostly ninjas, have the knowledge to access their spirit if it is powerful enough, able to do things like that. He has something called the Torn Sky Blast he effortlessly obliterated an F-16 attack chopper with." Kevin said.
"Damn!" Raiden said. He then fell back with the rest of his systems shutting down.
"Raiden?! Come on, buddy, answer me! Raiden?! RAAAIIIIDEEEN!" Kevin shouted desparately.
"I think we're done here." Ryu said, powering something else up.
Just as Raiden's friends began to fear the worst and expected Raiden to be vaporized, Ryu did a completely different type of ninpo and restored Raiden to perfect functioning health, snapping him back to consciousness.
"What?!" All three members of Raiden's current chat questioned.
"We're on the same side here. We weren't trying to kill each other. I was worried it wouldn't work due to you being a cyborg, but apparently, it has." Ryu said.
"Well then, let's finish this." Raiden said, walking up to Ryu and holding out his hand.
Ryu reached out and shook his hand, smiling, although Raiden couldn't tell under the mask. "Let's." He said, then they both ran, hacking through the rest of their enemies to reach their goal.
Reasons for the outcome:
1: While Raiden is stronger, seen to be able to throw enormous metal gears, his strength maybe on par with Dante (Insieme, don't flame, please) Ryu is not much weaker, blocking attacks from the goddess who had his almighty dragon sword and defeating god-like creatures on a daily basis, plus he is much faster, moving faster than perception many times (therefore around 6 times the speed of sound) and disappears in a flash of light, indicating he can move at the speed of light.
2: Raiden is seen in canon and gameplay to hesitate and become incredibly volatile and inefficient at killing, whereas Ryu has never been seen to hesitate and kills his enemies with no second thought, giving him and advantage in brutality.
3: While Raiden could survive most of Ryu's physical attacks for quite a while, Ryu's Ninpo would be able to easily destroy Raiden with its many diversities and at the very least could do severe damage and fry his circuitry, which is just as bad as killing him.
4: I may have already said this, but Raiden is capable to surviving many things normally fatal: impalement, getting the living shit kicked out of him by a psychotic senator who couldn't be so much as grazed without the Murasama blade and can throw giant heaps of metal and effortlessly send him flying, missiles, getting smashed and crushed by buildings and even massive plasma rays, so he could survive most of what Ryu was throwing at him, except electric currents, which would damage his circuits.
5: Doktor is canonically seen to tell Raiden the limits of the HF blade, not being able to cut through everything and it has to significantly damage any enemy before slicing through them, meanwhile Ryu is seen to slice through enemy limbs with single slices and can destroy any enemy and break their armor without weakening it, also the Dragon Sword is physically indestructible (cannot be destroyed by non-magical mean) while the HF blade was rather easily broken by Armstrong, who is not much stronger than low-level bosses in Ninja Gaiden, so Ryu's blade is superior in strength and endurance.
6: Raiden is at a SEVERE range disadvantage, having almost no ranged weapons; except for the one knife is his sheath he NEVER USES, while Ryu has an enormous arsenal of weapons effective at any range. Raiden isn't actually canonically seen to have ANY weapons other than his sword. Honestly, I was being nice by only having Ryu use the scythe and dragon sword and giving Raiden the pole arm (which, by the way, Raiden's pole arm is the ONLY unique weapon that's actually efficient in the game. The shears are WAY too slow and you can only throw around the sai.)
7: Raiden's techniques, while some are unpredictable due to his unique, self-taught style, he also uses a large variety of samurai techniques. Ninjas in general are used to fighting predictable samurai, but Ryu regularly defeats samurai-esque opponents. Also, Ryu fights a far wider variety of enemies than Raiden and many of his enemies have similar abilities as Raiden, plus Raiden is a straight-forward thinker and therefor would never be able to comprehend many of Ryu's enemies.