Chapter 18. A Sea of Darkness

Every guide had their own way to visualize an esper's corrosion. Some saw it like a billowing smoke, and visualize their guiding like an exhaust that sucked the smoke away. Some use a rusty sword as a visual and imagined themselves chipping at the rust. It was one of the first lesson guides would receive on their training course.

But Zein never received a proper training course.

Zein didn't see the corrosion inside the esper through analogical visualization. He looked straight into the root of an esper's system; their mana core. In the first place, corrosion didn't happen all over an esper body, it happened on their core, taking root like a disgusting black vein coiling up their soul. It was probably why he had such an effective guiding, because rather than taking a roundabout technique like visualization, he attacked the roots of the problem.

It wasn't that the teaching was wrong. It was just that most guides could not sense this mana core. Zein, thanks to his stigma, could sense his own core and with time and hard practice, managed to sense other people's core too, provided that he had access to their system through guiding.

But it was also wrong to say Zein didn't visualize. What he visualize, however, was the esper's mana core. And he always saw them as a body of water.

Body of water that was full of mud. It was this mud that he would wash over with his guiding.

Depending on an esper's core strength and mana quantity, the visualization ranged from a mere puddle to a pond. He had once guided a 5-star esper that felt like a lake during his first year in the borderland.

But Bassena Vaski was...

A sea.

A sea of darkness.

It was like he had dipped himself inside a pool of black ink that swirled ominously. At first, he thought it was the corrosion, but if that was the case, then it would mean the esper was on the verge of eruption already.

No, the corrosion was not the darkness, but the chains that were swimming inside the sea, like slithering snakes.

"Ha...haha..." Zein chuckled. If the whole sea was drowned in these chains...for the first time in a decade, Zein felt his confidence in handling an esper's corrosion faltered. The last time he felt like this was during a dungeon raid, although his dwindling confidence was caused by the monsters then.

It wasn't that he didn't think he wouldn't be able to handle it, but drastic measures might...

Drastic...measure...?

Again, that sense of deja vu.

But before he could properly dig into his poor memory, a husky voice shattered his daze. "Hey, are you alright?"

Zein blinked. He'd been staring blankly at Bassena for a while after throwing the question about the esper's mana pool. Or sea, rather.

"Did you say something?" he asked, rather dazedly.

Bassena tilted his head, observing the guide blank's eyes that slowly regained focus. Only after making sure that Zein had come back did he ask. "You can sense other's mana pool?"

"Ah...yes," Zein had never told anyone about this, for a good reason.

Normally, people couldn't see or measure others' core. What they could do was measure aura—the magic energy esper emitted outside. But it was different than seeing the whole capacity of one's magical reserve. It was akin to taking a peek into someone's financial savings. While some might proudly brag about it, most would be miffed.

But there was nothing Zein could do about it. As soon as he was connected to an esper, he could see it. And it was because he could see it that his guiding was so on point.

Zein observed Bassena's face, trying to see if the esper felt upset about it. But rather than looking angry, Bassena looked intrigued instead.

"How is it?" he asked.

Zein blinked. How...was what?

"How's my mana pool?" he repeated the question with a smile.

Zein had yet to decipher what kind of smile was that, but he decided to answer truthfully, like usual. "It's like a sea..." although Zein obviously had never seen a sea before. He just attached the name of the largest body of water he knew, because that was how Bassena's mana pool was. The largest he saw.

"So it's big?" the man smirked, and Zein would roll his eyes any other time, commenting about how esper was always obsessed with size.

But not today. Because even 'big' felt inadequate to describe it. "It's massive," he said instead, and the smirk stretched wider.

The smirk, however, vanished with Zein's next words. "And it's dark..." Zein closed his eyes, peering into the sea of darkness once again, since Bassena didn't seem to mind it.

Darkness...and chains...

The longer he spent inside the darkness, the more he felt familiar with it. It wasn't the kind of darkness that scared him, like an abyss. Rather, it was the type of darkness that he felt when he closed his eyes and fell asleep. It was the kind of darkness that enveloped him and made him float.

And it was the chain that disturbed the soft, smooth darkness. Zein looked at the chain with annoyance, like mosquitoes that disturbed his sleep. He looked at the chains with disdain and sent a torrent of water to wash away the chains.

Hmm...

He felt like he experienced this before. But it was heavier, more hectic, and he felt like the space wasn't this big...

"You're going to crash into me, you know," Bassena kindly informed the guide, whose body was leaning closer and closer to him. The hand that grabbed him had also tightened, reminding Bassena of how the guide grabbed his arm agitatedly yesterday.

But instead of pulling himself back, Zein brought his other hand up and covered Bassena's mouth. "Sush, I'm thinking."

And with that short order, Zein actually leaned his head to the esper's chest, eyes closed, breathing slowed.

Where is it? This nagging feeling of familiarity? It tickled him so much he started to feel itchy.

In the end, though, he still couldn't remember, and he lifted his face with a frown. "Ah, damnit!" he cursed in a low voice, to Bassena's bewilderment. He stared into the amber eyes with an even deeper frown, and started to open his mouth. "Hey, where exactly—"

"Hey, love birds, can we start the real briefing now?" Han Shin clapped his hand, and both the esper and the guide turned their head with a frown and click of a tongue. "What? Just get a room if you want to be private!"

Without feeling any remorse—or rather, with a feeling of accomplishment for disturbing his friend's moment—the healer waved his hand while pointing to the screen across the table. Soon, the Unit's record on the Deathzone was displayed on the screen, and Zein started to focus on the briefing with a professional mentality, even while he dutifully proceed with the pre-cleansing.

The question about where they met before was shoved far in the back of his mind.

* * *

"There are three main entrances that we usually take, depending on what kind of sample we need to gather," Ron explained the three dots along the black jungle of Section 04-2. "The furthest one opened up to a plateau, the closest one leads to a cliff, so we will need to either go around or climb it, which I don't think is possible with the researchers. So our best bet is to go through the middle one."

The male scientist, Eugene, looked at the compiled report the Unit made overnight for their perusal and nodded. "Yes, I think that should be the best option. You mentioned about a brook here, too, so that will be ideal for our objective."

"Are we going to move alongside the brook?" Ron asked while making a note on his map.

"It's better if we can go all the way to the source of water," this time, it was Anise that remarked.

At this, the scout frowned and tapped on his map anxiously. Zein knew all too well about the source of the man's difficult expression. His hand was tightening too, prompting Bassena to turn his head and looked at the guide.

"What is it?" he asked in a soft voice. The esper had slouched on the chair, perching his long legs into another chair like an impromptu guide's lounge.

He rubbed the hand guiding him with his thumb, eyes never leaving Zein's face until the guide answered in a whisper to not disturb the meeting. "We don't have any map further than a kilometer along the brook. The last time we tried to venture deeper, two died. So, looking for the source of water is..."

Zein stopped and turned to look at Bassena, who sat languidly while receiving his guiding. He recalled the vastness of the core inside the esper and thought maybe the man wasn't bluffing about protecting them.

"...what?" Bassena asked in wonder.

Zein had a way to make people feel perplexed with how deep and full of thought his eyes were while his face remained impassive. Paired with his beauty, it was usually left people feeling flustered.

'There got to be a lot of espers fell for him like this,' Bassena thought with annoyance.

"It might be possible," Zein muttered suddenly, and Bassena just blinked in surprise.

"Did you just imply getting to the source of water is possible because of me?" even while saying it, Bassena was still quite shocked. If it was other people who said it, he would just scoff.

But he remembered how Zein was grabbing into him while saying that he knew nothing of the Deathzone, so this statement came like a stamp of approval.

Bassena was...twitching, trying to hold himself from grinning widely.

"Do you have to reach the source?" Ron asked from across the room. "Even though we called it 'brooks', it's filled with murky, black water that is full of miasma. But for the beast, it's their source of nutrients, so there are a lot of them lurking around along the line. That's why it's difficult to go far through this terrain."

"Wait," Han Shin tapped his fingers on the couch, tilting his head at the scout. "Are you saying the only problem lies with the number of beasts present within the location?"

"Yes,"

"What about the terrain?"

"Of the approximately one kilometer we managed to chart, most of the land is quite leveled since a lot of beasts trampled on it. We obviously have no information beyond that, but from the endpoint view, there doesn't seem to be any cliffs or drastic slopes."

Suddenly, the healer laughed. "It's perfect then. If it's just about the beasts," he reached out his hand to gesture at the dining table. "We have the best predator," he said with a grin.

He said it with vigor, but the man himself was actually not listening to him. Instead, said 'predator' was engaged in his own world whispering with their guide, looking weirdly affable and full of smiles.

"...Hey," the healer called on exasperatedly. "I said get a room!"

Finally, Bassena tore his gaze from Zein and stared at his friend. "What? Of course it's possible with me," he just shrugged with an easy smirk, as if he'd been listening to them.

"Don't get cocky," Zein said disapprovingly, and the smirk was erased from Bassena's face just like that.

Han Shin, an ever-petty one, promised himself to report this behavior to their guildmaster. Also, he made a mental note to include a recommendation of having Guide Zen recruited into Trinity because apparently, someone who could tame Bassena aside from their guildmaster existed in this world.

But for now, he just glared at Bassena and focused on the exchange between Ron and the researchers.

"We don't know how far the source is, or how long it'll take to reach there, so it's not the definite goal," Eugene said. "But one of our tests is to be conducted near a body of water, the larger the better. So we'll take as far as we can."

"Might I know why?"

At that, Anise stood up and put a holographic projection device in the middle of the coffee table. It showed them a projection of another device that looked like a pole with a crystal on top, giving out ripples of energy.

"Our main objective here is not to collect samples, but to map the Deathzone and to test this device," her computer-like, monotonous voice rang out.

"And that is...?"

"Mist—Ron, you might be wondering how are we planning to camp out for two weeks while bringing civilians and a guide, right?" Han Shin flashed a deep smile.

"Ah..." Zein exclaimed softly from the dining table. Right, he'd been forgetting about this one.

Deathzone was no different from a massive dungeon outbreak and basically had morphed into some kind of open-field dungeon. With such an environment, even low-star espers would find it suffocating to stay more than a few days. Zein could tolerate it to some point with his constitution, and he could hang on by coating his body with magic energy. Even then, he would be too tensed and uncomfortable to be able to sleep.

And now they even brought along two civilians, who, by the look of it, were not the athletic type. So how could they even plan to stay there for two whole weeks? Not to mention, unlike the dungeons that had a degree of a safe area, there was nothing like that inside the Deathzone. There would be a need for a constant watch during the night and any rest period.

Even for a Saint-class esper, that kind of constant vigilance would take a toll on his mind, and might progress the corrosion quicker.

"So what exactly is that thing?"

Anise, who previously always wore a stoic face, cracked a proud smile. "It's a portable terminal for safe-zone manifestation," she announced it like a mother announced her child's name.

But it mattered not in what kind of manner the scientist called it. The important part was the implication of the words 'safe-zone'.

Again, Bassena felt his hand being gripped tightly. "Safe-zone?"

"That device can declare a safe-zone?" Ron widened his eyes until it seemed like they wanted to jump out of their sockets.

"No, no, not 'declare'!" Han Shin immediately waved his hand to reject the statement. "It's just a device, not a deity, geez..."

"Then what—"

"Calm down, our Miss Anise will explain it."

It was understandable that people who'd been spending their time in the borderland felt agitation toward this piece of device. It wasn't even for the 'safe' of the safe-zone. Just for the thought that it could provide them with fresh air was mind-blowing enough.

The scientists would know this best, since they were the ones who got the most impact from how suffocating the air of the borderland was. Even inside the building, who was coated with anti-miasma material, the air still felt uncomfortable. So, Anise was brightened up, thinking that the fruit of her invention would have such a huge impact on other people just motivated her further. "Of course, we can't imitate what the tower and the temple can do. After all, they used the fragments of a celestial being for it."

She glanced at Bassena, who was the source of this information. After all, only those who managed to finish the last trial had access to the peak of the tower, and thus found out what exactly kept the miasma and the beasts away from the structures.

"What we developed here is closer to what guides do," Eugene continued the explanation.

"...it can purify miasma?" Zein muttered in response.

"Bingo!" Han Shin shot the guide with his finger. "It's our peak creation. It absorbed the miasma in the air and the ground in a certain radius and turned it into a magic energy that will be shaped into a barrier."

Which meant, as long as one stayed inside the device's radius, they would be protected from miasma and the beasts. In that case, even civilians would be fine inside the Deathzone.

"Of course, just like guides, it won't be working instantly. It needs time to completely purify the miasma and manifest the barrier," Eugene explained further.

Han Shin took it from there and for once displayed a serious expression. "And our objective here is to see how far it could perform inside a heavy environment like the Deathzone."

Ron tapped on his chin while looking keenly at the device. "What about the radius?"

"Well, since it's still in development, we only managed to create one that could hold a twenty meters barrier for now."

"For now?" Zein straightened his back. "So there's a possibility for an upgrade?"

The healer turned his head to look at Zein, smirking at the guide. "Well, wouldn't it be better if we can make one that could encompass a city?"

Encompassed a city...

a safe residential area...

Zein felt like choking, as his eyes flickered and trembled.

A safe...red-zone...