If that was the case, it would explain things. Rui was an all-rounder, furthermore, his Martial Art was adaptive evolution. It was centered around the concept of overcoming by changing to overcome.
Thus, any hurdle, obstacle, or impedance could serve to stimulate his Martial Art. He would strive to overcome those problems by growing specifically to be able to handle them.
This was what he had done his entire time as a Martial Artist. The most recent and greatest example of it is the Shionel Dungeon. He had set the goal of being the first clear the Shionel Dungeon, an almost insurmountable task that only the most powerful Martial Artists in the Squire Realm were capable of even considering taking on.
The sheer number of Martial Squires that competed in the Shionel Dungeon back when he had yet to enter the Shionel Confederation was incredibly large. It was an abysmal herculean task to surpass all of them and clear the dungeon before all of them.
Yet, setting this task for himself allowed him to surpass his limits to an extraordinary degree as he went above and beyond to fulfill this daunting objective. He ended up creating two grade-ten techniques in order to overcome them; Riemannian Echo and Void Forestep.
Would he have created these techniques had he not subjected himself to the overwhelming difficulties of being the first to clear the Shionel Dungeon?
('Almost certainly not,') Rui shook his head. ('Those techniques were created as a result of trying to overcome specific challenges that came only because I subjected myself to the original challenge in the first place.')
The only reason that he ended up creating a technique centered around spatial sensing was because of the sensory jamming effects of the Shionel Dungeon.
The only reason he ended up creating the Void Forestep technique was to be able to handle taking on the Root in the final battle. Had it not been for that one cause, perhaps the Forestep technique would have never been created, or perhaps he would have created the Forestep technique a decade later.
('It's not just the training decisions that one makes that will shape the way and rate at which one's Martial Art progresses,') Rui realized. ('The challenged one is subjected to in their circumstances also affect the development trajectory of one's Martial Path.')
His eyes widened as he came across another realization. ('That's also probably another reason the Martial Union organized Martial missions in such a sophisticated and rigorous manner.')
Organizing missions by their field; whether they were offensive, defensive, or any other kind helped not only because it allowed missions to be completed by specialists who were especially qualified for the job, but also allowed them to face challenges that were relevant to their specialties, allowing for the conducive circumstances for growth.
With Rui, things were different from an offensive or defensive Martial Art. He was an all-rounder, which means he wasn't strictly limited to a particular kind of challenge for it to be effective. That theoretically meant that he could find opportunities for stimulation easier than other Martial Artists.
However, did that mean all-rounders were superior?
('No…') Rui shook his head.
The degree of stimulation depended on many personal factors, but one of them was the affinity between the challenge and the Martial Art and the Martial Artist. All-rounders could take on all kinds of challenges, but they didn't have a great affinity with any one particular type.
Specialists on the other hand had great affinity with the challenges relevant to their field and could derive great stimulation and opportunity for growth.
In that regard, he suspected that he was going to see something special from Kane this time. The training in the Thundering Valley was right up his alley, it was built for him, even. Following that logic, Kane ought to be able to develop much greater stimulation and opportunities for growth from these circumstances than Rui did.
Rui certainly intended to make the most of this situation, however, that did not mean he could do it to the same degree as Kane. Granted, Rui also possessed an advantage at being disproportionately able to develop techniques and add individuality to his Martial Art with greater ease and effectiveness than any Martial Squire he had ever seen in his entire life, so he wasn't sure if Kane would necessarily be able to exceed him.
It all depended on what he had in mind. Rui knew that Kane didn't have much experience with developing new techniques. In fact, this was most likely his very first time creating a technique fully from scratch.
Rui wondered if making it a competition and keeping it a secret was a good idea after all. He could perhaps use some help from Rui in making whatever concept and idea he had in mind real, without necessarily losing any individuality. Rui was good at realizing extremely ambitious concepts, if he limited his help to that, it could prove to be of great use to him, all while Kane retained pretty much all of the individuality he would gain from adding the new technique to his Martial Art.
('Eh, if it doesn't work out, I can always help him after,') He shrugged individually. Rui didn't need any reminding that, no matter how young he looked and felt physical, he was still incomparably older than Kane. There was a sense of patience and composure that came with age and experience in him that Kane lacked.
In some regards, he could not treat Kane as an equal, he was still effectively a child from Rui's perspective. Thus he decided to ultimately go about developing his own technique without being overbearing or intrusive.
If Kane wanted help, he could just ask, he definitely knew that Rui would help him if he did that. Thus it was best to let him initiate that.
The best outcome was that it would end up being a smashing success and he would truly surprise Rui with the results of all of his training.