After introducing the basics to him, such as the feelers and rudimentary structures, Damon taught August the most important spell he had conceived of to this date, isolators. Isolators took the form of dodecahedrons that tethered themselves to the soul. They looked similar to medieval maces.
Their purpose was to isolate the magic inside from the rest of the fourth dimension and create a mixture of this unaffiliated magic and their own affiliated magic. When half of the amalgam was composed of affiliated magic, the affiliated magic would gain dominance and transform the remainder of the mixture into neutral affiliated magic.
This allowed them to regain any magic that they had expended in the past and increase their souls' maximum capacity over time. Luckily, Damon had designed both an active and a nexus version of this spell. When the nexus spell was created and it began to work, it would fill their souls with magic at a fixed rate. It could be turned off if they had reached maximum capacity and back on when they needed replenishment without issue. They wanted to automate it so that it would turn itself on and off automatically, but they couldn't engineer a way to measure a soul's capacity relative to its maximum, so they put that idea on hold until their situation became stable and they had spare time.
Because he used the nexus versions of isolators, their structures occupied a fair portion of August's soul. He estimated that he still had access to anywhere from 75-80% of his soul, but the rest had been commandeered.
Although Damon could keep teaching him the other spells that he had designed, August instead insisted on working on his own spells because he was dissatisfied with Damon's versions. It was only an immature attempt to assert his superiority, but Damon relented and let him go off on his own.
They couldn't move yet because August was still ill, so they took the time to continue developing their repertoire of spells. August's first objective was to rework the feelers so that the information they fed back was more comprehensive and easier to read.
After what they estimated to be a week's worth of effort, August had finally redesigned one of the feeler's pipes so that the format it translated it into would emphasize chemical energy related to objects above a certain density, allowing it to see objects and liquids much easier than the energy in the air.
Although this version's structures consumed more magic, they both elected to use it over Damon's iteration because it allowed them to see solid objects easier.
August would only use feelers as an alternative to his regular senses, so he needed to be able to interpret things as quickly as possible, allowing him to get the gist of things at a glance.
Some of Damon's feelers were still his own version because his own version allowed him to hear better, but he largely used August's. This was because August's allowed him to see easier, which would help him feel normal again. He needed to feel normal to try and offset the psychosis that they both predicted would come.
Although Damon could sense everything August could, he couldn't do so with ease. What this meant is that it was still a form of sensory deprivation. When he was not intentionally contacting his soul, he was fully deprived of everything, including some forms of thoughts.
Although he had his thoughts, they were difficult to articulate unless he intentionally contacted his soul, likely because of his abnormal physiology. He was also having increasing difficulty recalling memories that were in certain forms.
Any memories he had of his previous life that included images and sound were becoming increasingly cloudy. He could remember everything in this life perfectly, but he was losing who he used to be because of the nature of his vessel. They didn't know exactly why he was losing his memories, but they theorized that they could stop this by giving him a new vessel.
On the fourteenth day, the day after August had finished his redesign, they decided that August was healthy enough to travel despite eating old fish and tainted water. The immune systems of August's species were unusually effective. However, there was still one final investigation to conduct.
"Damon, I've been meaning to ask, but what's the neutral magic in the necks of some of the corpses?"
"Neutral magic? What do you mean? Are you sure that it's neutral magic?"
"Yes, I'm sure that it's neutral. You didn't put it there? I thought it was some kind of research tool you made."
"You aren't talking about my feelers, are you?"
"No, I know what they look like, and this wasn't it. When I was reengineering my feelers, I made a structure that ignored air but put more emphasis on neutral magic than I wanted and not enough on other kinds. When I was tweaking that version, I noticed that there were structures around the C3 vertebrae of some corpses that I didn't put there."
"I didn't put it there, either," Damon claimed. "In fact, I didn't even know about it until you told me. Are you sure that you're not mistaking it for something else? Show me."
August demonstrated before Damon copied him. Sure enough, there were tiny structures made of neutral magic in the upper necks of some of the bodies. While the other variants of feelers that they had developed were all efficacious, they were not perfect. They were all finetuned so that they would only show what they needed to show and excluded other things.
The versions that they had developed all ignored neutral magic to a large extent because they could already sense the neutral magic that their souls were composed of, so such a small amount hadn't registered and hadn't been fed back to them, leading to their ignorance.
"This shouldn't be possible," Damon said, perplexed.
"You don't think it could be leftover souls, do you?"
"No, that's not likely. Only some corpses have it, but if they were souls, then all of them would have it. Another thing I noticed is that they are only in those that are the same species that you are. It's more likely that it's connected to that. Another thing that I noticed is that the quantity of the structures is correlated with the coverage of their armor. Those that are more heavily armored have more magic there. It might be the source of the armor. Why didn't you tell me this sooner?" Damon accosted. "This could be valuable."
"I thought that you already knew and were just ignoring it for some reason," August complained.
"No, I wasn't. Regardless, I think we know what it might be now. Remember the scavengers a few days ago? When they came through, they were looking for something in particular, but they weren't taking anything that would normally be valuable, like the arms and armor. This means..."
"... they were looking for something else, maybe this," August finished Damon's thought for him.
"Before you revived," Damon continued, "I saw one of them bend over and eat something during one of their excursions. I thought that it was strange because I didn't see him take anything out of his bag and simply chalked it up to not looking hard enough, but now, I think that I may have been wrong. He was more heavily covered when he came back last time. I thought that he had taken medicine or invested in something when he was back in his camp, but I was likely wrong. Chances are, these structures are the source of both their armor and yours."