Hello everyone! It's time for another chapter of this story! But first, there are the reviews from last time!

Void Reader: You'll have to wait and see what exactly Project Zero is and how it affects the story!

That's everyone, so let's get started!

Nightstalkers

Mechanical Mayhem

The trio of Freedom Fighters awoke the next morning, preparing to tackle the new day.

The events of last night however remained in all of their thoughts. But more importantly, was a question.

What did Robotnik want with them?

"How'd you two sleep?" Sally asked.

"Good…" Tails groggily responded, letting out a yawn afterward.

"Fine," Sonic answered. "It was a bit hard to fall asleep though."

"Why's that?" Sally continued.

"Just thinking about Robotnik. More specifically, what he wants with me… Cause if I am this Hero of Legend… Then Robotnik has to have some sort of motive."

"I think we've all been wondering about Robotnik. Maybe we'll get some more info today."

The other two mobians nodded, they didn't have any better ideas to figure anything out. The best they could do for now would be to stay alert.

Tails rubbed the sleep from his three eyes as he sat up and immediately felt the need to hunt run its way through his system. His hunting urges just kept getting stronger. They were still manageable for now, but he wasn't completely sure how much longer he'd be able to hold off on giving in to them. Shaking the thoughts from his head, he made his way to his feet. "So what's the plan for today?"

"Whatever Robotnik has in store for us I guess." Sonic answered, "Judging by what we know about him so far, he'll probably have some more tests for me to run or something."

As if on cue, Orbot entered the room, with Cubot trailing closely behind.

"You're awake." Orbot began. "The doctor requests your presence in the workshop."

"He's got more things for you to do!" Cubot added.

"We'll be down in a second," Sonic responded.

The two robots left, leaving the trio to themselves once again.

"Okay, so here's the plan." Sonic began, putting on his cloak and boots. "I'm gonna destroy that robotic copy Robotnik's made of me. It's got one of the Chaos Emeralds inside it. The issue is that Robotnik has the other one. If he doesn't give it to me again, you two will need to go after him and get it while he's distracted with his tests. I don't think he'll put up much of a fight himself."

"You sure you can take out that machine?" Sally asked.

"I'm not, but after you two get the Emerald from Robotnik, you can help me. I don't think it'll stand a chance against all three of us."

"Seems like a plan to me." Sally added, "Tails, you ready for this?"

"Ready as I'll ever be." The fox responded, putting his headband and cloak on.

Sonic got to his feet. "Let's do this then."

The trio took the elevator down to the workshop, where they found Robotnik and his robotic Hero of Legend waiting.

"Took you three long enough." The doctor began. "I don't have all day to run these tests you know…"

"Well, we're here now."

Robotnik sighed, "Let's get started then, we're behind schedule…"

The trio followed Robotnik outside, the robotic Hero of Legend trailing behind the group as they walked through the snow. Soon, they arrived once again at the testing area.

"Fox," Robotnik began, pointing at Tails. "You're with me. You other two stay here."

Sonic shot a glance over to Tails, reminding him of the plan they'd discussed. The fox followed behind Robotnik to the nearby elevator platform that let up to the observation deck, catching a glimpse of the purple gemstone tucked into the man's cloak as he did. The scientist walked to the railing and Tails stood next to him as he spoke.

"You'll notice I've made some modifications to the Hero of Legend since yesterday." The man's amplified voice began, as he watched the machine turn to face the two mobians across from it. "I took the liberty of testing them this morning before you arrived and they work flawlessly. Because of this, I've decided the two of you have outlived your usefulness to me."

Tails' eyes went wide as he registered what Robotnik was saying. But before he could react, the man's mechanical hand grabbed the fox by his scruff. Holding him in the air just far enough away to avoid the fox's kicks.

"As for your friend," The man continued. "His unique genetic makeup makes him the perfect candidate for a test subject. It's been a long time since I've gotten to work on any sort of organic subject, let alone one as interesting as your fox friend here… I'll leave you two to your fates though. Hero, dispose of them for me if you would."

Robotnik turned away from the railing and started back toward the tower they'd been staying in, taking Tails with him as he did. Sonic and Sally stood paralyzed in shock as the man walked away. Shooting each other worried glances as the machine standing across from the two of them drew its sword, the Chaos Emerald in its chest starting to glow a faint green as its digital eyes sized them up.

"Sal, go after Robotnik!" Sonic said, "I'll deal with the machine."

As Sally ran toward the elevator that led up to the observation platform, Robotnik's robot appeared to block her path, kicking up a storm of loose snow as it dashed forward at blinding speeds.

Sally extended one of her ring blades just in time to block the machine's sword swing, attempting a counterattack with her other ring blade, only to be met with a block from the machine's weapon. Sonic appeared next to her, delivering a glancing blow to the machine's outer plating with his dagger. Taking a step backward, the robot glared at the duo as it prepared its weapon to strike again.

"We'll make this quick," Sonic said, raising his dagger before rushing forward, with Sally close behind him.

-X-

"Let me go!" Tails yelled, trying and failing to kick Robotnik in the gut as he struggled against the man's grip.

"You're a feisty one aren't you?" The scientist responded as he entered the door to the tower. "I'm just making good on my promise."

"What promise…" Tails began before his voice trailed off. Remembering the late-night conversation he'd had with Robotnik, he remembered exactly what Robotnik had said he could do to him. "You're going to modify my DNA!?"

"You're smarter than you look! Given your unique parentage, you'll make the perfect subject for me to test the Hero of Legend on. Once I remove some of the… Less desirable parts…"

Entering the elevator, Robotnik placed his hand on the hidden panel used to access his old laboratory.

"Why are you doing this!?" Tails asked as the elevator started upward.

"As I mentioned to your friends, they've outlived their usefulness. I simply needed data from your hedgehog friend to fine-tune my machine."

"But why!? Why do you need us?"

The elevator opened and Robotnik stepped into his old laboratory, the same one that Sonic, Tails, and Sally had explored the other. Tails noticed, however, that the computers in the room were turned on, and a large, cylindrical chamber with glass walls now extended from the floor to the ceiling. Dozens of wires and other electronics hooked up the machine to the computers.

Robotnik pressed one of the keys on his keyboard and the glass retracted back down into the floor. The man then grabbed a nearby syringe, causing Tails' eyes to go wide as Robotnik moved to inject whatever was inside into the fox's arm.

While his struggle managed to delay Robotnik, the man was eventually successful in sticking the syringe into the fox's arm. Pressing down on the plunger to inject the solution.

Tails immediately felt as if his blood was on fire. He screamed in pain as his entire nervous system lit up in absolute agony. Robotnik then unceremoniously dropped the fox inside where the glass was, the walls of the chamber slowly rising back toward the ceiling. Tails tried to get to his feet but the pain rushing across his entire body made even thinking difficult. By the time he eventually stood, the chamber had long since sealed and Robotnik was now sitting at his computer nearby, watching the fox's actions with great interest.

"That solution should be taking effect any moment now…"

"What… Did you do to me!?" Tails exclaimed, his voice heavily strained with how much pain he was in. He had to support himself with one hand against the nearby glass wall to avoid collapsing again. His entire body trembled constantly as wave after wave of pain rushed through him.

"Just made it a bit easier for your… Other half to take control. I want an opportunity to see this first hand…"

Tails' eyes went wide and he tried to yell at Robotnik, but he was surprised when his voice came out as nothing but a series of deep growls and snarls. Panic flooded his senses as he tried yelling out again, only getting the same deep animalistic noises once again.

Whatever Robotnik had injected him with was slowly letting his Nightstalker half take over. The fox felt the same urges to hunt from this morning only growing with each passing moment, he tried to keep himself calm, but that was becoming increasingly more and more difficult as even his thoughts changed to the language the Nightstalkers used.

Tails tried to strike at the glass that held him trapped, scraping at it with his now extended claws to no avail. His entire body still ached from whatever Robotnik had injected him with. Feeling weak and exhausted, he soon collapsed to his knees.

His vision started to blacken as he steadily lost control over himself, eventually, his mind went blank and his vision went black as he was entirely consumed by his primal instincts…

-X-

Clouds of powder snow in the courtyard outside showed obvious signs of a struggle. Sonic and Sally were locked in combat against Robotnik's Hero of Legend. The robot charged forward with blinding speed, an ability that had been granted to it by Robotnik's recent modifications to its systems.

Sally threw herself to the side as the robot swung at her with its sword, the attack struck a nearby tree as it missed, creating a large gash in its trunk and sending a spray of wood fragments flying from the impact.

Sonic did have to admit that Robotnik's evident modifications he'd made to the machine since their last fight was making this much harder than it needed to be. The fact it could now move much faster than any of them meant they could barely land a hit on it, especially since they were busy trying to dodge the attacks coming from the robot.

The robot's head swiveled around, spotting Sonic with its mechanical eyes. The gemstone in the machine's chest started to glow more intensely as it prepared to charge once again, only to be struck by a slash from one of Sally's ring blades. While the plasma weapons failed to break through the machine's armored plating, they did knock off the machine's balance and sent it falling to the snow. Before Sally could attack it any further, however, the robot delivered a punch to her stomach. Knocking her backward enough for the machine to stand back up. If Sonic didn't know better, he could have sworn he saw a tinge of anger in the machine's digital red eyes.

The gemstone in the machine's chest started to crackle with energy and the glow from it now blanketed the area around it in a bright green light. Sonic decided whatever the robot was up to couldn't be good and charged toward it, trying to stop it.

A golden hue surrounded the robot for a moment before an explosion blasted Sonic backward and sent the snow around it flying in every direction. The hedgehog tumbled end over end, losing his grip on his dagger which flew out of his hand, disappearing into the snow. Eventually coming to a stop, Sonic let out a groan.

"That hurt…" He thought, but before he could get to his feet, Robotnik's machine was standing above him, sword poised to plunge into his chest.

Adrenaline rushed through the hedgehog's veins as he rolled to the side, hearing the blade of the robot's sword strike the snow next to him as he did.

With adrenaline running through him as he got to his feet, Sonic could now feel the sheer amount of Chaos Energy radiating off from the Emerald. It hung in the air like a thick fog, blanketing everything around the area. He could feel the energy flowing around him, filling his entire body with a warm tingling sensation.

All he needed to do was tap into it…

But doing that was a lot more difficult when you also had to worry about dodging a sword swung by your robotic duplicate.

Sonic stepped back out of the path of the robot's sword, continuing to pull on the Energy in the air around him, but he knew he couldn't dodge forever.

He needed a distraction. Luckily, he had a perfectly good one.

Sally delivered a strike to the robot from behind, having finally reached the two of them. While her attack didn't do very much to the robot, it did pull its attention away from Sonic, leaving the hedgehog free to continue gathering Chaos Energy. The warm sensation he'd already been feeling only continued to get stronger and stronger. He tried to turn it into something useful, he could use a weapon right now, especially since he'd lost his dagger somewhere in the snow.

Called upon by his thoughts, a spear of Chaos Energy quickly materialized in his hand. The weapon's energy glowed a bright green, matching the glow of the Emerald in the Hero of Legend's chest. Acting quickly, Sonic rushed toward the robot, stabbing at it with the surprisingly light spear.

The weapon pierced the robot's outer plating like a hot knife through butter. Sparks erupted from the machine's torso, and the lights that formed the machine's eyes flickered momentarily, almost as if the machine was caught completely by surprise. It was distracted long enough for Sally to land a solid strike to the machine's arm with one of her ring blades, knocking the sword out of its hand in the process. The robot rushed backward as it assessed the damage to itself. But before it could finish the spear still embedded in its chest violently exploded. Sending Sonic and Sally tumbling to the ground and kicking up a giant cloud of loose snow.

"Probably should throw it next time…" Sonic said.

Carefully standing up, the two of them turned to where the robot had been. As the snow settled they found nothing left of the machine except for the scattered pieces of its outer plating. The Chaos Emerald in the machine's chest had survived the explosion, along with the robot's sword, which still rested in the snow nearby from when the machine had been disarmed by Sally.

Sonic picked up the sword, it was a bit heavier than the dagger he was used to, but given he couldn't see his weapon anywhere, it would have to do. Sally grabbed the bright green Chaos Emerald that had powered Robotnik's Hero of Legend and tossed it to Sonic.

"I think you'll be able to use this more than me." She said.

Sonic was still in a bit of shock from what he'd just done. Had he always been able to create things like this? He quickly snapped out of his thoughts as he remembered about Robotnik. The man had taken Tails, and given he'd just recently ordered Sally and himself killed, whatever he had planned for the fox couldn't be good

"Let's go get Tails." He said.

Sally nodded and the two of them ran back to the entrance to Robotnik's tower sanctuary. The heavy metal entrance doors were sealed shut, an obvious attempt by Robotnik at securing himself inside. Sally's ring blades failed to even visibly damage the doors.

"Sal, step back," Sonic said, focusing on the Chaos Emerald he held in his hand. This time the Energy he was trying to draw on came much more easily, the Chaos Emerald was a seemingly limitless fountain of power Sonic could draw from, and almost immediately another spear of Chaos Energy materialized in his hand.

Hurling the weapon at the door it exploded on impact, damaging the door but failing to break through completely. The hedgehog threw a second spear at it, causing the door to buckle under the weight of a second explosion but it still refused to give way.

Finally, the third managed to break through, blowing a hole big enough into the metal that Sonic and Sally could squeeze through.

Robotnik was nowhere to be found inside the building's workshop, but Sally had a suspicion of where he might have gone.

"Remember that hidden laboratory Tails showed us?" She asked.

"That's probably a safe bet," Sonic replied as the two made their way over to the elevator.

They seemed to have no trouble calling the elevator itself, and once they pressed their hand to the specific panel on the wall, they were on their way upward to Robotnik's laboratory."

As the elevator doors opened, the two were immediately greeted by the sight of Robotnik. The man stood by the main computer, his attention focused on the screens in front of him. With the opening of the elevator doors, Robotnik's attention turned to the two of them, surprise evident in the man's reaction.

"How did you two…" He began before stopping himself. "Seems those modifications were insufficient then…"

"Where is Tails!?" Sonic said, anger dripping from his words.

"I'm glad you asked…" Robotnik responded, gesturing over to the nearby glass chamber where Tails was.

The fox seemed to be unconscious but otherwise unharmed, something that surprised both of the other two Freedom Fighters.

"So here's how this is going to go…" Sonic continued, another spear of Chaos Energy materializing in his hands. "You're going to give me Tails and that Chaos Emerald of yours…"

"Fair enough, you can have your friend," Robotnik replied, pressing a few things on his keyboard. It wasn't long before the walls of the glass chamber Tails was in started to retract back into the floor. The man reached into the fold of his cloak, but instead of producing the Chaos Emerald, he activated a small device attached to his waist. Suddenly, a bubble-like protective field appeared around him as he took a few steps backward, a section of the wall behind him opening up into a secret room.

"But I'm keeping the Emerald." Robotnik continued, Sally tried to attack the man with one of her ring blades but the shield around him simply deflected her strikes.

"As much as I'd like to stay and chat, I'm sure you have a reunion to get to. I hope you don't mind that I made some modifications to your friend here…" Robotnik said before passing through the doorway he'd opened.

The section of wall closed, sealing Robotnik off from the Freedom Fighters.

Figuring they'd deal with Robotnik later, Sonic returned his attention to Tails, rushing to the fox's side now that the chamber he'd been in was gone. The hedgehog gently shook the kit, trying to wake him up.

The fox stirred from his sleep. Looking up at Sonic.

"Tails, you're alright! Had me worried there for a secon-"

Sonic was cut off mid-sentence by a loud snarl from the fox. Tails extended his claws and swiped at the hedgehog, forcing Sonic off of him.

"Tails relax, it's just me!" Sonic yelled as the kit got to his feet. The fox stood hunched over, brandishing his claws as he stared at the other two mobians in the room.

Sonic and Sally's blood ran cold as they realized what exactly was happening, the bloodlust evident in Tails' blue eyes and expression confirming their suspicions.

Tails had lost control….

The fox lunged at the two of them, one simple thought on his mind….

It was time to hunt…

Alright everyone, that's it for this chapter! I hope you all enjoyed it and I'm sorry to leave it on a cliffhanger but hopefully there will be an update soon! In the meantime, let me know what you thought in a review! Until next time!