Treasure of a Thief (3)

Since he couldn't force his way through the security system, Shui tried to figure out what it was using to detect him so that he could reach the treasure chest without being found. Considering that his blade had been detected while in mid-air, he removed weight from the list of candidates, and while there were some unlikely possibilities, he settled on light, sound and presence. 

To test the system's ability to detect light, Shui carefully crafted an illusion of himself mentally, and then projected it inside the system's range. This illusion method made it easy to construct realistic images using astral will, but the burden on the user was much greater than most illusion spells.

The system didn't seem to react to the illusion, so he slowly pushed it closer to the treasure chest. Once he was in reach of the chest, Shui tried adding substance to the illusion by using mental control to allow it to exert force, but the moment he started his connection to the illusion was cut, and it dissipated.

"I suppose that would have been too easy. Still, it doesn't seem to rely on light, at least not alone."

The next metric to test was sound. Objects with sentience usually had no presence, but if he tried to move something to make a sound, whether it was through physical or spiritual touch, then his aura would stick to it for a while. However, he would be able to solve this issue if he used martial intent since it was inline with nature. As for using martial intent to take the treasure chest, that wouldn't work because although the rules seemed to be different, Shui was still inside an inviolable domain that prevented such actions.

Shui took out an ingot of spirit iron from his storage ring and moved it inside the range of the system. Fortunately, the system didn't react, so he moved on to the next step of the test. Using martial intent, he hit the ingot, which caused it to vibrate and produce a short but high-pitched sound. That didn't elicit a reaction either, so he tried to get it to the treasure chest like he did with the illusion, but once again, his connection with the metal was cut and it fell. He was worried that he would also be cut automatically if he got too close, but in this case the metal was untouched so it didn't seem to have any effect on physical matter.

"It looks like I have no choice but to approach it."

The final test also involved moving spirit iron, but this time he purposely attached his aura to it before moving it inside the system's range. Just like the time with Sui, the spirit iron was gone without a trace after a bright light. With this it seemed obvious that the system was using presence detection, but just because he knew that didn't make this easy for him.

Even at his best, due to possessing divinity Shui had lost the ability to completely conceal his aura, and had settled with spreading it to the extent that it became imperceptible. Unfortunately, even if he spread his aura as thin as possible, he doubted that would be enough to fool the system. Still, that wasn't to say he didn't have an idea.

To test his idea, Shui tried triggering the system with just his aura. He pushed his aura forward to the extent that it filled the passage, but there was no reaction. This confirmed that even if it could detect his presence, he had to be in its range to be attacked. This was great news since he only had the basic structure of the technique he thought of to solve this problem, and needed some time to refine it.

Once he confirmed that he could meditate in peace, Shui sat cross-legged and focused on his aura. Thanks to the experiences he had so far, Shui was decently proficient at manipulating his aura, but it was too much and too dense for him to perfectly conceal. The most he had ever accomplished was spreading his aura so thinly that his own presence became like that of a ghost. However, even then he was still like a clump within the mist of aura so it wouldn't be impossible for the system to detect him. Fortunately, the system had one flaw that he could take advantage of; it didn't discriminate between inanimate and live targets. Each person's aura was unique, but that same aura could be spread among many objects.

Shui started by distributing his aura into ten orbs around him. Aura had no solid state, so the shape was just to make it easier to visualize. When his aura was separated into the ten orbs, they each possessed roughly the same amount of aura that he couldn't remove from his body. For the next test, he used bronze coins to serve as the core of the aura orbs, and then sent them into the system's range at different paces while ensuring that they stayed close together.

This time the system didn't react until every bronze coin was within its range, and even then Shui was able to detect a slight lag between the erasures. With this, Shui could confidently finish his technique. 

Thanks to the pressure of this situation, Shui had gained two key insights that would help him conceal his aura and pass the test. The first insight was that aura was easier to attach to solid objects than air. It seemed obvious, Shui had neglected this detail previously because he hadn't thought it would fix his issue. However, by using the bronze coins he had proved that even this accurate system would hesitate if it detected an even distribution of the same aura with different cores. As aura was a unique attribute, if he attached it to a place it would be possible to make it seem like he was there even if he wasn't, and vice versa.

The second insight was an improvement over his previous method of spreading his aura thinly. What he realized was that if he wasn't able to make the innate aura of his body as sparse as possible, then he had to make the surrounding aura as dense as his body's. By using these two insights, Shui constructed the technique he called presence masking.

There was nothing inside the passage he could use to tell the time, so Shui ignored it and focused on the technique. He quickly settled on the theory, so the only thing left was to practice. Once he felt that he had done enough, Shui began releasing his aura towards the treasure, while ensuring that its density matched his body's. That alone wouldn't elicit a reaction, so once it reached the treasure chest, he summoned Sui and sent it into the system's range.

He held his breath as it got closer, but a calm expression returned to his face once it passed through without a reaction. He knew that it still wouldn't be able to reach the treasure chest like this, so he stopped it at about halfway there. Now it was time to test presence masking with his body.

Shui didn't have anything to block the system's attack, but his eyes could pick up its response a second before the action, and the speed intent he possessed would allow him to surpass light speed and escape if necessary. As he reminded himself of these failsafe measures, Shui stood up and slowly approached the system's area.

He tried to keep each step as steady as the last while moving forward. He hesitated once he reached right before the system's range, but that only lasted for a moment. He was fully prepared to flee as fast as possible, but he faced no attack after his foot made it through. This gave him more courage to bring his entire body within the system's range, and there were no surprises. 

Shui was ecstatic that his technique worked, but he kept his emotions under control as he walked to the same distance as Sui, and then stayed two steps behind it while both of them continued on. When Sui was about to reach the treasure chest, Shui stopped it before the connection was cut and then took the lead. 

'Almost there.'

He had guessed that the cut only affected the spiritual, but before he reached the treasure chest, Shui felt like his consciousness was about to be blown away.

'Now!'

Though he wasn't sure if something would happen to him, Shui had cast a delayed spell on Sui that would trigger once he began to lose consciousness. Once this condition was met, Sui pushed his body towards the treasure chest. He wouldn't be able to do anything else, but Shui had safely reached the treasure chest.