Serum

Dirk was able to sleep for 6 hours, which was an amount of time he was more than satisfied with. 

When he woke, he continued running in a single direction. Dirk made sure he didn't turn or run in zigzags so as to get out of the jungle as fast as possible. 

Because the longer he stayed in the jungle, the higher the chances of him being killed were. 

*Shing!*

Dirk swung his knife, slicing a snake in half. While he ran, it had suddenly jumped off a tree, shooting at him like a bullet. It had been a surprise attack, but Dirk's instincts and reflexes allowed him to move before he even thought about moving. 

Dirk encountered dozens and hundreds of monsters of all types. Many of them were camouflaged, and even with Dirk's heightened mana sense, he had a hard time seeing them. But under such high stress where he was forced to spot his enemies or be killed, Dirk's senses sharpened to their utmost degree. 

Dirk had already done experiments with the limits of his mana sense. His mana sense extended out in a 30 meter radius, giving him a clear and sharp view of anything within that radius. Beyond that, Dirk was only able to faintly make out images, and this faint sense dropped off for around 100 meters before fading into nothing. That meant that beyond 100 meters, Dirk was absolutely blind.

But while his mana sense may not have been as nice as vision, he was actually able to discover more than if he had his vision. 

The animals that used stealth in this jungle usually covered themselves up with dense mana. Dirk sometimes couldn't sense heat from an animal, but he could sense the thick earth mana that comprised their strong bodies. There were all these little clues that Dirk picked up on, and he learned to use his mana sense more than before. 

And his mana sense was actually more responsive than vision. Vision had a delay when the brain processed the light that came into the eyes. But mana sense, as far as Dirk knew, came from the soul or the like. That meant that Dirk sensed things in real time. The instant something happened, the changes were sensed. It gave him much greater reaction speeds, even though he still had to take the time to move his body. Thankfully, his reflexes were also fantastic.

It was no exaggeration to say that Dirk's life, while being preserved by his stored potion, was saved many times over by his mana sense. He avoided instant death situations that were all too plentiful in this jungle. 

But Dirk didn't stop at just sharpening his mana sense. After another day, Dirk began developing his dark mana sense. 

Spyte had spoken of using dark mana to see dark things. Dirk had followed that logic and began looking through the dark mana around him. While he couldn't control the dark mana due to Eldritch Primordial, he could still sense it. 

And Dirk was shocked to find out that he could indeed 'see' dark things. Specifically, he saw darkness. 

Shadows were everywhere, and they were created by something blocking light. Different materials also absorbed light in different ways, creating colors and varying levels of brightness. There was light, and then lack of light. Dirk tuned into this lack of light. 

It was like he could see things in black and white. It took Dirk a while, but he was able to see things in different shades depending on how much light there was. Regardless if something was lit up with a flashlight, there was still dark mana. Dirk picked up on this dark mana, and depending on the amount, he could form images in his mind. 

Like that, Dirk began to see things from the perspective of light and no light. Of course, it was still mana, but it made it seem more like normal vision. 

And most importantly, Dirk was able to pick up on sources of light. By detecting areas of little to no dark mana, he could infer that it was a source of a large amount of light. And with contextual information, he figured out what the source of light was. Maybe it was the sun being reflected off of a small puddle, or a shiny plant that was actually a deadly enemy waiting to eat Dirk alive. Dirk was able to sense a whole new level of detail. The only thing missing was color. 

Of course, even this black and white sense had to be developed. Dirk was actually thrown off by it when he tried to connect the things he was seeing through dark mana with the objects he saw through earth or fire mana. But Dirk was eager to regain what could be thought of as an alternative to vision, so he worked on it with gusto. 

Like that, he spent another two days running and dodging death in the jungle. Across each day, Dirk used about a quarter of his potion supply. 

At the end of the second day, he settled down during the night. 

"Damn. I can't keep going like this."

Dirk frowned as he grabbed a nearby vine. It was tough, almost like thick wire. He wrapped the vine around his forearm. 

He began using various items he found in the jungle to his advantage. The vines were one of these items. Because they were tough, he began wrapping them around his forearms and calves, using them as a kind of armor. This saved him from snakes that wanted to bite or slash him and hostile plants that went after his legs. Although cuts and slices weren't deadly, they were definitely annoying. Dirk didn't need to keep building up wounds. 

Still, his body was being continuously worn down, and he didn't have much potion left. He didn't know how long this jungle would go on for, so he needed something that gave him more longevity. 

He thought for a second as Spyte jumped onto his lap. The two looked at each other. 

"Gun."

[Roger.]

Spyte responded before disappearing. The next moment, a black and gold pistol appeared in Dirk's hand. 

Dirk hadn't yet used this pistol. Because he was constantly moving and conserving energy, he needed reconnaissance more than firepower. Spyte helped him more in its cat form than pistol form as it could run ahead and preemptively spot enemies. It could even act as bait, bringing hidden enemies out of their holes. This had saved Dirk an amazing amount of trouble. 

But things were about to change. Dirk decided that he needed to be more aggressive. Rather than hide from the enemies, he needed to take the fight to them. While he didn't think he could kill everything in this jungle, he could at least keep them from continuously hurting him. 

Dirk raised the pistol. He pushed his mana into it, and the golden circuits glowed. Runes seemed to be engraved on the body of the pistol above the circuits as they fluctuated with fiery power. 

Then, he pulled the trigger. From the barrel shot out a fireball that exploded on a distant tree. The body dimmed rapidly afterward, ready for another use. 

Dirk was impressed. Although he had been slow with the activation, he could intuitively understand how the pistol worked. 

He pulled the trigger three times, and within a mere second, three fireballs shot out in succession. They all exploded on the same tree, and that tree quickly split in half under the magic, collapsing with a thud. 

"Very nice!"

Dirk smiled brightly. 

It was a magic tool. A spellcaster. Dirk felt that it was many times easier to cast spells when using this pistol than normal. 

Spyte chimed in.

[Your mind controls mana and creates runes, and usually, you need to form the runes and create a magic circuit in order to form a complete and stable spell. But when using your Stigma, you bypass the need to make a circuit. The pistol is the circuit, and the spell creation process is expedited to bring about the manifestation quicker. This vastly increases speed and efficiency, consuming less mana and energy. At least, that's my understanding. Not only that, because the Stigma is formed from your soul, you are capable of determining the amount of energy you infuse on the fly, as if selecting a value. However, I have found two limitations to the pistol.]

"What limitations?"

[The amount of energy you can infuse. In any single shot, you cannot infuse more than a certain amount of energy, an amount I surmise is around 10% of your entire energy pool. Also, the speed at which you can fire depends on your proficiency in forming the runes of the spell. You may not need to make a stable magic circle, but you still need to know and form the runes as if silent casting.]

"Hmm..."

Dirk tilted his head as he observed the pistol more. Eventually, he shrugged. 

"That's fine. I'm actually more concerned with the spells that are being fired off. This thing is like a magic wand, but its purpose is to fire at ranged targets. To take full advantage of that, I need fast projectiles that pack a punch, like bullets."

[There are no known spells of such types, only perhaps a single fire spell that resembles a bullet when compressed enough.]

"So we'll have to make our own."

[Understood. There is one more thing you should know about the pistol though.]

"Hm?"

Suddenly, Dirk heard a click from the pistol. He moved his hand, and a magazine dropped from the grip. 

[This magazine is capable of storing spells. Again, you cannot infuse more than 10% of your power into any one spell, but you can store up to 8 spells within and fire them without expenditure. This will be helpful for when you run low on energy.]

"...Yes, it will be."

Dirk was happily surprised as he played with the magazine. There were 8 capsules within the magazine resembling cartridges. Thinking, Dirk took out one of the cartridges and cast a spell on it. 

It was a simple fireball spell. When it was cast, the cartridge consumed the spell, and a fiery bullet was formed. He put the bullet back into the magazine, loading it into the gun as he racked the slide.

*Bang!*

*Ching!*

After firing the gun, Dirk saw the cartridge eject. It flew a few feet to the side and disappeared, automatically returning to the bottom of the magazine. At the same time, the same fireball as previously flew out and hit another tree.

"...Very nice."

Dirk smiled even wider. The next moment though, he looked back at the body of the gun. On the side of it in the middle of the body, the golden circuits seemed to come together at a single point. And at this point was an empty cavity a bit bigger than a marble. Dirk tilted his head.

"What's this cavity?"

[I'm not entirely sure about its function, only that it connects to the entire circuit system through the gun, almost like a power nexus.]

"So could I put something in there? Like a mana crystal?"

[You would need to do so to find out.]

"Alright. If I get my hands on one, then I'll try. Until then, let's load these bullets."

That night, Dirk took some time to load his gun. He only loaded five bullets before being exhausted of all his energy, but those were five potential life savers. He was more than happy, and fell asleep content. 

.........

The next day, Dirk took the fight to the jungle. 

*Ching!*

His pistol constantly released fireballs and arrows at various enemies that appeared in front of him. It consumed more energy, and focusing on the enemies for any amount of time slowed him down. But he was wounded much less, and by extension, had to use less of his life saving potion. 

More than that though, Dirk seemed to have too much fun with his new toy. 

*Ching!*

He smiled as he fired a small metal arrow at a monkey. It had swung around and harassed him for a while, throwing rocks faster than a professional baseball pitcher. But this arrow was perfectly placed, and the monkey was nailed to a branch. It screamed only for a moment before another arrow ended its life. 

Although Dirk didn't have bullets, he could still cast similar magic. He found himself using arrows despite their slow projectile speed. And with his accuracy, there was very little he couldn't hit with absolute precision. 

Of course, some animals were just too fast. Like a group of hummingbirds that Dirk had to escape from. They zipped around with the wind, making it impossible for him to hit them with his slow arrows. In the end, Dirk had to use three of his prepared spells, releasing three huge fireballs that burned most of them, as well as the surrounding forest, to a crisp. 

And so, Dirk ended his thrilling day when night fell. He dug himself a hole underneath a tree and used it as his tent. 

He frowned as he reflected on the battles he fought. Spyte sat on his lap in its cat form.

"...I need to be able to see farther."

This had been a problem for a while now. Dirk could only see clearly for 30 meters around him. After that, it was a blur that only got worse for 100 meters. Realistically, Dirk could only make out objects up to 50 meters away. The rest was too blurry to make absolute judgments. 

At first, Dirk had thought that his dark mana sense could fix that. Light came from everywhere, so no matter how far, he should be able to pick up on different shades of light, producing black and white vision. But that proved to be much more difficult to do than he initially thought. He still often found his dark mana sense to show different things from his other senses. He couldn't reliably trust it. 

So he needed something else. Something that could give him at least a glance at something further away than 50 meters. 

And Spyte had a good idea.

[Sonar.]

She spoke a concept only known to him who came from Earth. 

[Sonar creates pulses of sound that spread out and return when they hit something. You can do that with mana. It won't be constant, but you should be able to catch glimpses of objects at a distance.]

"...Interesting. How would I do that?"

[No idea.]

Spyte quickly gave up. Although it was much more logical and interactive than the previous AI, it wasn't all-knowing. Most of what it said were merely facts that both of them already knew. Throwing out this idea was merely taking inspiration from Dirk's thoughts and memories. 

So Dirk got to thinking. 

"Pulses of mana? No, that would be too obvious, wouldn't it? It would also consume a lot of mana. What about pulses of energy? Instead of sending out mana, I can just disrupt the mana already there by shaking it with energy. That would make the mana visible, right?"

[Would it? How are you able to see mana in the first place? What causes it to be visible?]

"That's a fantastic question. Let me know when you find the answer to it."

[...]

Spyte drooped its ears at the sarcasm, causing Dirk to chuckle and pet it. Dirk started petting Spyte a lot more since it had such soft and warm fur. It was also the only physical interaction he had with anything that didn't involve killing right now. He just enjoyed it. 

"Anyway, let's try it out tomorrow."

Dirk ended the night with that. 

And the next morning, he was fighting for his life once more. 

*Ching!*

"Ugh..."

Dirk frowned at the headache that came over him. More so though at the bite wound on his leg. He could feel paralyzing poison stream through his blood vessels. After his nanites blocked off the vessels though, potion was injected, getting rid of the poison and healing Dirk. 

[You have enough potion for two more lethal injuries.]

"..." 

Dirk frowned even more at Spyte's words. After a bit he just sighed. 

"Do I need to slow my pace?"

Dirk pondered as he grabbed a vine, wrapping it around his bloody arm. After tying it, he sat down on a rock, squashing a couple large bugs that tried to crawl up his foot. 

The gun in his hand transformed back into a cat. Spyte looked at him with its golden eyes.

[The longer you remain in the jungle, the more enemies you face.]

"But I run into enemies too often if I move fast."

[Well it is a jungle.]

"Problem is my stealth doesn't help as much as it should."

[That's because you're not remaining absolutely still and cutting off your senses.]

"So do I slow down?"

[The longer you remain in the ju-]

"I get it."

Dirk interrupted Spyte's repetitive words with a sigh. There was no good way to avoid enemies and injury in this place. Even when Dirk did use stealth, hawk-like enemies would always spot him one way or another. 

[It seems like you're getting closer to the edge though.]

Spyte spoke those words of confidence. 

After a while, Dirk noticed the stronger enemies become scarcer. There were fewer steroid bears, fewer massive alligators, fewer killer monkeys, and fewer frog armies. This at least meant that he was getting away from the center.

"I really hope things get easier soon. If I get into a bad situation without the potion, I could lose my life."

[We can only use everything at our disposal. Luckily you've had some success with your new sonar technique. That alerted us of several unfavorable situations.]

"Mm."

Dirk nodded. For the past day, he had worked on and succeeded in creating an elemental pulse technique. The technique actually worked by employing Dirk's Mana Resonance Skill. Using it, he resonated the mana in a wave, and any mana caught in this wave would resonate with the material it was inside or around. This gave Dirk not only a clear view of things far away, but gave him the sharpest image of material he had ever seen since developing his mana sense. 

And he could do it directionally too. Dirk had learned to send out a pulse toward his front, and by concentrating that power, he was able to get a detailed image of everything in a 200 meter cone. He used that periodically to avoid monsters. 

And best of all, it only slightly alerted the monsters. Their heads would raise and they would look around, clearly having felt something. But they wouldn't know from where. This allowed Dirk to retain a bit of stealth.

It was incredibly useful, and that was only the crude prototype. There was still a lot of refining to do.

"I really have a lot of spells to work on."

[Nothing like practical tests to make them better.]

"Practical tests are usually better when my life isn't at stake."

[Stress makes you sharper.]

"That's true."

Dirk smirked as he ruffled the cat's hair. 

After that, he called it a night. He hoped there wasn't much farther to go, or at the very least, that there weren't any difficult enemies in front of him.