It was astoundingly complex and equally beautiful.
Intricately designed signals manifested all around Elsmeth and Israfel as they stood outside on the periphery of the zone of darkness energy stemming from the dungeon.
It was as though Elsmeth was watching his demon companion sculpt several dozen pieces of art simultaneously, with each piece harmonizing to create something even more marvelous than when apart.
Alternating units of conceptual meanings intertwined as Israfel continuously added more to the elongating chains.
What he could only accomplish by feeling his way through the process as his body used darkness energy to generate the Attribute of the Dead was watched in real-time by Elsmeth.
Resembling tsunamis of information, the signals shot out as multiple enormous waves spreading through the darkness energy in every direction.
Scouts of the Guild would normally be of a lower Tier than the dungeons they kept watch of, as their task was to monitor, not to fight.
Clerics were the most critical component of a scouting party. Just as demons could often detect their approach, they too could sense the movement of the demons.
While the demons could track the disappearance of the Attribute of the Dead when stolen by light energy, Clerics could sense the flow of light energy towards the 'Source of Evil', as they would put it.
Both demons and the portals they protected had a constant stream of light energy that would flow towards them that could be traced by Clerics. The specific flow was obscured by the zone of darkness energy around dungeons, but if either left the zone, the shift in energy would be noticed.
The Demon King had to lace his spell with magic that would befuddle the senses of all scouts outside of the various dungeons so as to make them treat the sudden influx of light energy toward the strengthened dungeon portals as normal, but the magic did not add anything to affect their ability to track demons leaving the dungeons.
Because of this, other demons would likely attempt the usual method of tunneling away within the safety of the zone, extending the dungeon's underground network instead of leaving.
But that wouldn't be necessary for Elsmeth and Israfel.
Israfel was already talented at Tier 4, and his natural talent stuck with him after his advancement. His plan would most certainly not be able to be executed by any other recently advanced Tier 3 demon, but his confidence was unwavering.
The surging tides of Undead Attribute signals went to all sides of the zone before breaking out of it entirely in search of its prey.
It was coded to hunt one specific target with all other life forms being ignored.
Deer, squirrels, and even more magical creatures like Arcs, birds with extraordinarily small bodies and large wings composed of arcs of electricity, continued to move about utterly unaware of the invisible signals flying past them.
Elsmeth's perception surprisingly managed to follow along across the distance the signals traveled, watching them as they homed in the unsuspecting humans.
Upon reaching their goal, they pierced through the circulating energies of the various Mages and Clerics amongst the adventurers, only losing a small percentage of Undead Attribute to the Clerics' light energies in the process.
Then, along with the mana they traveled along with, the darkness energy signals with the Undead Attribute infiltrated the bodies of the adventurers in a variety of ways. Some incorporated themselves into the cells of their host's nervous system. Others disguised themselves as hormones and other small molecules used normally to signal within bodies.
The end goal was the same regardless of the method. It was to achieve a higher level of influence than Israfel had been able to achieve before in his mind control. Previously, he was capable of controlling the actions of his victims by consciously issuing them commands. If he stopped at any point, he'd lose dominion over them and they'd recall everything that occurred.
Now, he wanted to achieve something closer to what he was capable of with his undead. He wanted to issue a set of temporary commands that he didn't have to focus on any longer after the initial casting of the spell.
His goal was a success. The thoughts of all of the adventurers around his dungeon were influenced to ignore his departure and to forget about ever encountering his spell after it stopped controlling them. They had noticed the small moment went the signals began invading them, but that memory would be entirely erased.
That being said, despite Israfel's happiness at his accomplishment, there was one flaw that Elsmeth noticed.
Inefficiency.
First, there was the expenditure of energy to send out the signal in all directions. A few simple modifications to the conceptual meanings of the signals and their homing abilities would be vastly improved. Rather than sending out so many signals to track the humans, a few would suffice so long as they could seek out the targets in an easier manner by having greater affinity.
Then there was the method of infiltration. The pathways of circulation of the adventurers' energies were completely visible to him, and he saw many more convenient routes for the signals to penetrate than the ones they took.
The controlling process would take less time and there would be significantly less loss of Undead Attribute.
He glanced over at Israfel who was standing with a contented smile.
While not the case for everyone, when most people learn a language, they pick up additional things like social cues, situational awareness, and a basic understanding of navigating conversations through the minefields known as the feelings of others.
The knowledge Elsmeth possessed didn't include any of that.
"That was a bit wasteful."
"What do you mean?"
It was just like the rhetorical question from before, a senseless inquiry on something where the answer was already known. He meant that the spell was wasteful. How else was he to phrase it?
Tilting his skull, he tried to think of a better way to convey his meaning.
"There were a number of unnecessary and incorrect steps taken in that spell."
At the words spoken with a purely analytical tone, Israfel looked at him with a deadpan expression.
'Is this skeleton I summoned seriously lecturing me on how to use magic…'