A huge bombshell had exploded in Rui's mind. Suddenly, everything from before was starting to make sense if what Rui was beginning to suspect was true. It was all starting to click.
The lack of footprint trails incoming and exiting the area of the hunt despite the fact that smaller and lighter creatures had footprints incoming and outgoing out of the area. Then the presence of its footprints around the carcasses. It's impressive elusiveness, being able to appear and disappear in and out of an environment far too easily and inscrutably.
All of this could be explained if the creature was primarily subterranean or is primary mode of transport was subterranean fundamentally!
This wasn't an absurd notion. Even on Earth, subterranean fauna was found worldwide and included representatives of many animal groups, mostly arthropods and other invertebrates. However, there was a number of vertebrates, although they were less common.
This paradigm was not necessarily true in the world of Gaea, however. The world of Gaea was filled with many strange and exotic species that were capable of far more than the fauna on Earth was. Although travelling through subterranean means of transport to accomplish what the target of his mission had accomplished and shown to be capable of was not possible by any Earth-based fauna, the same could not be said of fauna of the world of Gaea.
By travelling underground, the target creature would be able to travel to and from locations without ever leaving a trail of footprints. However, it may need to come above ground to actually hunt and eat its prey, which would explain why its footprints were there at the site of the skeleton carcasses.
Everything seemed to fit.
('Almost everything.') Rui corrected. (There's the question of how my Seismic Mapping didn't sense it.')
Seismic Mapping allowed the user to understand the shape of the topography as well as position of objects on the land via sensing and understanding seismic radiation. If the creature was moving underground incredibly fast, wouldn't it generate immense amount of seismic vibrations and radiation?
('Maybe not.') Rui conjectured. ('Maybe its body is optimized for geodynamic subterranean to such a degree that it could travel through the ground at incredibly high speeds without producing much disturbance through the land.
This wasn't uncommon in other modes of transport. Birds could fly through air an incredible speeds without ever producing a single sound ever.
Same for many aquatic creatures, that zipped through water at vigorous speeds.
If the target of his mission was similar in that nature, then Rui could understand why he had difficulty perceiving it, especially when he had never been within a hundred meters of it. Who knows, perhaps he would actually sense it clearly if he were closer.
The problem was, the creature was gone just as he arrived.
('That's another issue.') Rui frowned. ('Was it just dumb luck that it left just a little before I arrived?)
Upon this revelation, Rui wasn't sure anymore. There were a few more odd things with his subterranean travel hypothesis.
('How does it detect its prey or the direction it wants to travel in or general topography underground?') Rui wondered.
There's no way it could see or smell prey underground. Light did not travel underground and neither did odour. There was no air underground either, so how could it hear sound waves through the air?
('It might have a seismic sense similar to Seismic Mapping.') Rui realized. It was a bit of an obvious conclusion once one asked the question how the creature could perceive information while being surrounded by mud, gravel and rocks.
In that case even more things made sense. His horrible luck was no longer luck but an outcome of his target's sensing of his approaching. That begged the question, why did run away the moment it sensed him? It was an apex predator with prowess at the Apprentice Realm. It shouldn't necessarily be afraid of a single Martial Apprentice.
Yet it left the scene the second it sensed, assuming it did sense him.
('Was it because of how hard and fast I was running.') Rui wondered. He had used Parallel Walk and Balanced Direction while also using Outer Convergence to boost his speed and stepping power. Having used Seismic Mapping at the same time, he knew for a fact that every step he had taken generated enormous amounts of seismic radiation.
If the creature could hear through the land, it would have heard a creature causing explosions with every step it took. Every step had enough power to hurt even itself.
In this case, fleeing away was not a strange choice, Rui realized. He had given the creature an exaggerated impression of himself, causing it to simply flee evacuating the area before this new apex predator reached its location, rather than risking a fight to death with a creature that seemed extremely physically powerful.
('That would also explain why it never went after the largest herd in the Shaia Plains.') Rui realized. ('It must have sensed me using my Apprentice-level techniques to chase after the deer, and assumed that I was another apex predator native to the land hunting after that particular herd of six-legged deer, so it avoided conflict by hunting other herds of deer of gazelles that were scattered around the Shaia Plains.
Rui sighed in helpless resignation as he realized the measures he had taken to increase his chances of running into the beast had thoroughly killed any chance of him running into the beast even in a million years.
Rui exhaled, reminding himself that this was all deductive conjecture, rather an irrefutable proof. He had applied deductive and inductive logic to the data available and had made some basic presumptions of the target and constructed a well-thought-out possibility that had the highest likelihood of being true than any other hypothesis or theory that wone could conceive. However, he was not a zoological or ecological scholar, so his opinion didn't hold much credibility, even to himself.
('I need convey all of this to the Martial Union and the Ministry.') Rui realized. ('And I need to find some damn proof.')