Author's note: Thank you again E-Rank, Noonui, and Guest! It's always great to hear what parts people liked best. :) Lots of development going on in these past few chapters (including this one :3), but I do promise some action in the next!

Update 1/30/21: Squee, my first Sonic fanart! E-Rank totally outdid themselves with this capture of the heroic duo being not-so-heroic with one another (and Shadow mildly entertained by this), on DA (www dot deviantart dot com / whatisthisdefiance / art / Zenith-Ch-4-Color-Coded-Heroes-868745927). Thank you so much!

Chapter 4: The Tip of the Iceberg

Northern Hemisphere

"We're gonna have to land to the east," Tails said to the two hedgehogs, pulling the biplane up and away from the dense forest below. "I'm checking the map now to see what's available."

Shadow, back on the bottom wing, gave a curt nod, though a part of him wanted to simply jump off the plane and start the search below without his two acquaintances.

He needed the Chaos Emerald to do that, however, and he highly doubted that Sonic would let him borrow it for this venture.

Prior to leaving Angel Island, Tails pinpointed each of the other Chaos Emeralds' locations before they had disappeared. When he had mentioned the taiga, Shadow discreetly requested to visit that location first, knowing it was Rouge's last known whereabouts.

Sonic had argued immediately about his suggestion (unsurprisingly), mostly due to the fact that it was too far in distance when the other locations (particularly a populated city and a more temperate mountainous area) were identified. He stayed mum on the Chaos Emerald that had been located close to the coastline, of course.

Tails interrupted them at one point to pull Sonic aside, most likely to whisper to him that it was probably where Rouge had gone to retrieve the emerald.

Shadow felt like rolling his eyes, namely because the fox seemed to think that he was being inconspicuous about his deductive reasoning, and Sonic's fake, agreeable attitude afterwards made him want to cringe.

Nevertheless, he played along so the two idiots would pilot him there as intended. Seeing the sheer size of the forest they were flying over, Shadow's need for the Chaos Emerald to find Rouge was reinforced. She had briefly mentioned to him that the Chaos Tracker was leading her to this area, but beyond that she had been vague in where she'd been heading. With thousands upon thousands of square miles of dense forest to search through, never mind at a heavily reduced speed, it would have likely taken weeks to hunt down that energy trail.

The plane bounced unsteadily on the rocky terrain as Tails landed, which was the only indication that there was a lack of runway. The fox kid slowed the biplane atop what looked like a mesa, barely higher than most of the surrounding treetops settled at its base. A bitter wind chose that moment to gust through, and—while Shadow didn't outwardly show it—Sonic exaggerated his own shiver, complete with an annoying, "Brrrrr!"

"We're lucky it's fall right now," Tails commented, shutting the engine off and jumping from the cockpit to the ground, "out here I think the temperature can dip below -50 Celsius in the wintertime."

"Great, so instead of a hedgehog-cicle, I can become hedgehog soft serve."

Tails did not respond, but instead opened a side compartment in the plane itself. He pulled out a blue puffy jacket, his arm outstretched. "Here," he said, though barely got the word out before Sonic jetted over and slipped it on.

The jacket seemed to be of tougher material, which made sense since it had to cover over some of the blue hedgehog's back quills.

Tails pulled out a similar yellow jacket and, after some noticeable hesitation, pulled out a red one. He turned around and faced Shadow.

"Um, this is Knuckles', but should fit you. It's going to be cold, and—well … here." The fox thrusted the red coat in Shadow's direction, still holding his (presumably) own yellow one.

Shadow looked at it, then at Tails. "I will be fine."

"Take the stupid jacket," Sonic said next to him. "I don't care if you're the Ultimate Lifeform or not. It's colder than the shady side of an iceberg out here."

The black hedgehog let out an annoyed breath, but yanked the jacket out of the fox's hand. As he placed it on, he mumbled a small, "Thanks."

Nodding to him, Tails donned his own winter gear before rummaging through the compartment to grab his equally yellow computer.

These supposed heroes certainly had a color scheme they liked to keep to.

Shutting the metal door, Tails turned to face Sonic, who was currently pulling the giant hood on his jacket over his quills for extra warmth. "Ready?"

"When am I ever not?"

As the fox started typing commands into his portable tablet, Shadow made an effort to casually peer over the kid's shoulder and see the map he had drawn up. Sure enough, his tracker seemed to work quite efficiently, triangulating the unique energy levels of what appeared to be the blue Chaos Emerald. With a few more taps on the screen, the map zeroed in on its last known whereabouts, a digital compass popping up and pointing west.

"Nifty," Sonic spoke up from next to Shadow, appearing from nowhere. The black hedgehog let out a perturbed grunt and took a few steps westward, turning around impatiently when all he heard was his own footsteps.

Getting the idea, Tails' appendages started spinning, allowing him to hover a few yards off the ground and still holding his computer to guide them. He took the lead, easily swerving between the tall coniferous trees, but above the lowest branches and leaf-covered terrain dotted with stubborn patches of snow.

The jacket Shadow had borrowed was somehow breathable yet warm, and did not constrict his quills like he expected it to. He had a feeling the customized coats were the result of the prodigy he was currently following, and made a mental note to see if the kid would be willing to make him one for future use.

It'd be nice to not go through jackets on a daily basis, after all. He did wonder how these coats handled an actual spindash, though…

They travelled west for several miles, darting through some pretty dense foliage and uneven ground, before changing direction and heading slightly north. Several more miles later, Tails landed in a small clearing, his condensed breath coming in large, tired puffs in the steadily dropping temperature around them.

"It should be right around here," he stated, his eyes more glued to his map than the actual clearing. He frowned as he took slow, wayward steps, trying to gauge the last few feet from his signal.

Shadow was far too impatient for that. His rockets flared to life and he zipped in a circle, spiraling outwards until he was hit with that same unsteady feeling. Abruptly stopping in its midst, he hesitantly stepped towards its epicenter, every fiber of his being telling him to get away.

"Here?" Sonic sounded unconvinced, coming up next to him and searching around. He was completely oblivious to the negative aura.

"Yes."

Tails was close behind, one hand holding his computer and the other typing excitedly on the screen. His muzzle crinkled in earnest concentration, and before long a small antenna extended from the yellow contraption, a tiny light blinking on its tip.

"What is it?" Sonic asked both of them.

Everything that's wrong with Chaos, Shadow wanted to say. "Negative energy," he spoke out loud instead.

His rival rolled his eyes. "It's more than that," he insisted. "You actually lose a few shades of color when you're in it."

"That's physically impossible."

"You know what I mean."

He did, but he did not respond. To be honest, he was a little unsettled that it affected him enough to show an actual physical reaction. Sonic turned to Tails as the fox started mumbling something, but Shadow ignored them. Taking slow steps closer to the corner, he stood at the edge of a small crevice in the side of a rocky hill and exhaled a long, steady breath. He closed his eyes as the trails of unease floated around him.

A sudden tingle of a memory felt just out of reach. Shadow forced himself to calm his mind, willing the lingering energy to absorb into him completely.

"Shadow?" a small, frail voice called out. "Are you all right?"

"Yes," he answered her, pulling his eyes away from the large window. She approached him slowly, hands clasped in front of her. "Are you?"

"Just tired," she lied to him. He frowned as he studied her, and how she couldn't quite pull her back up straight. How her normally pristine blonde hair was mussed, limp strands dangling in front of her and hiding most of her face.

She was in pain.

"What happened?" he asked, coming up to her instantly.

"It's fine, really," she argued, even as he came up to her side to support her. Her weight instantly shifted into him, proving how much she was struggling.

"What did they do?" he demanded, slowly leading her back to her room.

"I—" she coughed, a long trail of dry heaves that halted their progress. She shook her head, even though Shadow had not said anything. He supposed he didn't need to; his anger was palpable.

"I just need to lie down," she finally got out, swallowing hard to prevent another coughing spell.

She was nearly two heads taller than him, but her hunched form made her seem so tiny and fragile, a shell of the young girl he remembered merely months ago. Her normally bright blue eyes were dull and glassy, Shadow only catching a glimpse of them before she purposely turned away.

The disease was progressing, and had been for some time. But this … this was different. He knew her grandfather was growing desperate, as any grandfather likely would. After all, Shadow was living proof of that.

But when it was determined that Shadow's powers were uncontrollable—when they had not mastered a way to transfer the Chaos that brought him to life over to this sick girl to heal her—exactly what else did he have planned?

…What had he done?

"I'm sorry, Shadow."

"Shadow?"

He blinked, the memory fading like the mist forming from his breath. He glanced to the right and saw Sonic staring at him, an arched brow completing his confused, mildly concerned expression.

"You zoned out there for a hot minute," he offered when Shadow just stared right back. "You all right?"

A frustrated growl escaped as he sidestepped away from the nosy blue hedgehog. "I am fine," he retorted, trying his best to mentally shake off the painful memory. The trail of negative energy faded somewhat as he moved to the other side, but its power was unmistakable.

He had felt this energy before … with her.

"Huh," Tails said in front of them. Shadow blinked again, disturbed that he had been so lost in thought that he'd missed both Mobians shuffling right past him. The fox was currently standing near the wall of the hillside, where the two large rocks converged.

"What is it, bud?" Sonic asked, his attention thankfully diverted from Shadow.

"Uh," he replied, typing on his tablet, "it's … I think I know what this energy is." He looked a little worried—guilty?—as he glanced back up at Sonic. "It's, well … I think it's replicated Chaos energy."

"Replicated?"

"You know, not … real … Chaos energy?"

That got a long groan from the blue hedgehog. "Fake Chaos?" he balked. "Like that emerald you made?"

"No, not like that," Tails insisted immediately, his eyes darting back to the screen. "The one I made had the same wavelength of a Chaos Emerald. This … this is different. Like a shift in the properties, which is honestly really complex..." the fox trailed off, his concentration coming back to his computer as he studied more of the information.

"Fantastic," Sonic grumbled sarcastically. "Like we need any more of that fake Chaos energy in the wrong hands."

"Hey!"

That apparently got Tails' attention, as he stopped what he was doing to glare at the blue hedgehog.

"I know you don't feel Chaos like we do, l'il bro," Sonic explained, looking at Shadow for support (who offered absolutely zero in return), "but fake energy just feels wrong. I mean, it blows machinery up! And now look what it's done."

Shadow raised a brow. "I thought you did not feel the negative energy."

"Well, I—I don't right now, but nothing good comes from this stuff!"

Tails seemed downright affronted. "This is way different than what I made, Sonic."

"I know," he consented, despite still sounding annoyed. His hands went up in the air in exasperation when he couldn't help but add, "But the end result is the same, isn't it?"

The hand holding the computer fell to the fox's side, his grip white-knuckled as he narrowed his eyes. "I don't know, last I heard it saved your hide in space."

He narrowed his eyes right back at his sidekick. "Look, it's dangerous. Chaos isn't meant to be controlled—"

"That's the entire point of the Chaos Emeralds and the Master Emerald, though!" Tails argued, his own hands (and computer by proxy) going up in the air. "They made them to control Chaos energy in the first place!"

Now both brows of Shadow's rose. This was getting interesting.

Sonic crossed his arms, which ended up looking ridiculous with his extremely puffy coat. "And they've nearly caused the end of the world how many times?"

"You—you use the energy to become Super!" the fox kid's voice raised, arms flailing about in the air. "They heal the environment!"

"Yeah, they heal what they've destroyed, you mean."

Tails' arms finally came back down, but his grasp on his portable computer somehow tightened further with his expression. "The fake Chaos Emerald I made was not meant to be infinite in its power. I was trying to hone a larger amount of energy. Do you know what that kind of prolonged power source could do for providing cheap energy to the world? What it would do for the environment?"

Despite the higher pitch in his tone, likely trying to win the blue hedgehog over, the only response he got was a scoff, followed by, "Until someone like Eggman gets their grubby hands on it—!"

"Enough," Shadow interrupted the rapidly heating argument, silencing them both with his tone. "This is Gerald Robotnik's design."

Tails' eyes widened. "Your creator?"

Exactly how much did these two know about him? Pausing for only a beat, Shadow ignored the question and continued, "I recognize it from … before."

"Well, if it is Eggman's grandpa,"—which was instantly followed up by a sound of disgust—"then I guess we know where we're heading next." Peering over to his sidekick once more, Sonic asked, "Where do you think he's at?"

"I thought all my ideas were bad and dangerous."

"Aw, Tails—"

Shadow rolled his eyes and walked away from the two restarting their bickering. A sudden thought, however, made him boldly turn around and walk up to the fox, yanking the computer right out of his hand.

"Hey!" both he and Sonic exclaimed.

"Do you have access to G.U.N.'s servers?" Shadow probed, tapping a few keys on the screen to bring up a command prompt.

Tails rubbed behind his head anxiously. "Er, well not officially." Avoiding any acknowledgment of Sonic's critical stare or tapping foot, the fox came up next to Shadow and pressed a couple buttons, executing a program. "Here," he said, pointing at the screen, "that should get you in."

Shadow hummed, recognizing the familiar files of G.U.N.'s network. He quickly sifted through the logs, looking for a specific one Rouge had mentioned. A couple of times he was blocked by a credential check, which he quickly inputted to bypass.

"Wow," Sonic said as he and Tails watched, "didn't think G.U.N. would give you full access to their stuff."

"They did not," Shadow responded absently, rapidly opening and closing files in his hunting.

Tails frowned. "Rouge gave you her security clearance?"

"Not officially," he mimicked back. Finding the folder he'd been searching for, he opened it and pulled up a specific report. "Two weeks ago, G.U.N. reported an unusual disturbance at these coordinates. Investigation proved to be unremarkable, but a storm caused the mission to be aborted early."

"Storm? What kind of storm would cause them to just up and leave?"

Glimpsing at the coordinates on the report, Tails answered before Shadow could: "A sandstorm. They were in Sand Ocean."

"Ugh, I hate that place."

"I thought G.U.N. controlled that area?" Tails questioned Shadow, ignoring Sonic's commentary.

"It was too volatile to maintain, and had remained abandoned for some time."

"Until now, I guess," Sonic grumbled out dramatically. Shadow handed the computer back to Tails, who took it, making sure to copy the information he needed before shutting down the connection.

He then gave Sonic a rather sour look before taking flight back in the direction they had come from.

The blue hedgehog sighed and nodded to Shadow. "Let's get going before he leaves us out here."

He zoomed ahead, Shadow taking one last cursory scan of the area before catching up. After a long back-and-forth inside his head (mostly with a lot of you don't care being echoed around), he finally let curiosity get the better of him and ran up to the side of his rival.

"Why do you disapprove?"

"What?" Sonic tilted his head, side-glancing him oddly before jumping over a few boulders blocking their path.

"Negative energy."

He groaned. "You mean fake Chaos energy? Why would you even ask? You know how bad it is."

"Yes. In the wrong hands."

"Seriously?" Sonic incredulously retorted. "You too, huh?" His attention returned to their route briefly, zipping through some fallen trees, before he shook his head at Shadow.

"Look how easy it is for it to get in the wrong hands then, Shads. We have enough to deal with keeping the Chaos Emeralds safe, y'know? We don't need fake stuff floating around, being used to blow stuff up."

"Gerald Robotnik did not make negative energy for that reason." A pang of sadness hit Shadow and left as quickly as it came when he added, "He wanted it to heal."

Sonic slowed down, staring at Shadow. "Yeah, well … it didn't work, did it?"

The blue hedgehog came to a stop. Shadow slowed a few paces ahead before stopping, as well. "…No," he finally answered.

Walking up next to the black hedgehog, Sonic gazed through the forest in the direction his sidekick had gone. "I know Tails means well. And he probably will save the world ten times over with his inventions." His expression darkened as he looked back to Shadow. "But messing around with Chaos energy is not the way to do it. The name says it all, right? Chaos is chaos."

Before Shadow could respond, Sonic frowned at him and said, "I see how much it bothers you. You know there is something wrong with it. I felt it too, when I used it for Chaos Control."

"Did it not work?"

"It did, yeah." His head shook as if he could get rid of the memory that way. "But it left me feeling sick for weeks afterwards."

Flashes of a frail little girl blocked Shadow's vision momentarily. "Sick?" he prompted.

"Not like a cold sick," Sonic clarified, still thoughtfully staring at the ground, "but like I was pulling in more Chaos energy—real Chaos energy—because I had used it."

"I'm sorry, Shadow. He thought it would work."

"Makes you wonder how someone who couldn't absorb Chaos energy that way would handle it, right?" Sonic rhetorically commented.

Shadow felt his blood run cold. "They wouldn't," he replied knowingly.

After all, he'd seen what it'd done firsthand.