After all, it would take an extra amount of effort to shield himself from his own environment, which would only make the difficulty of passively constructing these domains that much more difficult. It would have been ideal if his body was highly resistant to these conditions naturally.

Unfortunately, he hadn't engaged in too much body conditioning. After becoming a Squire, the only time he had was when he mastered Adamant Reforging, which was strong but a general boost to his durability and could not handle too much of a particular given environment.

"Do I really have to spend an additional year or two conditioning myself to handle the heat and cold without letting it affect my combat ability?"

Rui found the idea unpleasant.

He did not want to extend his time in this place beyond the stipulated two years, if possible. He also didn't like the idea of conditioning himself. The reason for that was that conditioning was inherently inflexible, which was incompatible with the concept of adaptively evolving. It also didn't work spectacularly with his systems of thought.

Unlike Flux Earther, which grew vastly stronger after he formed his predictive and SOUL models, conditioning was static.

Unfortunately, he also recognized that he needed it. Active defenses like Flux Earther and Inner Divergence had multiple points of failure and an extremely high threshold of mental engagement to be effective. In other words, making the wrong decision could reduce active defenses to zero, leading to death.

Static and passive defenses were much more reliable. No matter what decision the user made, they would always be reliable and did not require a high amount of mental engagement to function as always.

Rui's rationality refused to allow him to ignore the massive benefits of static and passive defenses.

"Damn," he cursed under his breath. "Do I really have to subject myself to conditioning? I don't even have the specialized training environments of the Martial Union--!"

Rui froze as an epiphany thundered in his mind. "Training environments...What if I use the domains that I am training as training environments to condition my body?!"

The more he thought about it, the more it made sense. What better way to condition his body to withstand his domains effortlessly than to use those very domains to condition his body?

"On top of that, conditioning training applies the principle of progressive overload, in that the load needs to be progressively stronger," he muttered himself. "My domains will start off weak in training and progressively get stronger as I master them. They are absolutely ideal for progressive overload body conditioning!"

Rui's expression morphed into one of awe as he realized how extremely efficient and resourceful these training measures were.

"In fact, I can use other domain techniques for the same purpose as well." He realized, growing excited. "I can use Heavenly Convergence to train my raw physical strength. I can use Sonic Singularity to train my internal durability. I can use Speed Void to train my maneuvering. I can even use Soul Void to train sensory techniques!"

He no longer needed to run to the Martial Union with their specialized anti-sensory training environments. In fact, he could drastically elevate the quality of body training that he was able to engage in without needing external resources!

"I could even create a domain to train my domains!"

...

Now, that was a little far-fetched.

Even Rui had to admit that that would be extremely difficult, even in theory, let alone practice.

For now, he was satisfied with two years of simultaneous domain training and body conditioning.

"It will probably take a little longer to get both done even if they're simultaneous," Rui admitted since he would need to take more care to ensure both happened properly without any sub-optimal divergences.

But it was fine.

He was still training extremely efficiently and completing two training sessions in close to the timeframe it took for one. To complain even after that would be too greedy, even for Rui.

With that, he had laid the specific objectives for his latest training phase. To create domains while using them to condition his body to be immune to them. A domain of heat and a domain of cold.

"Project Muspelheim and Project Niflheim."

The names came to him almost immediately.

He couldn't resist.

After all, he named the Yggdrasil system after its namesake the Tree of Life in Norse mythology. Muspelheim and Niflheim were, respectively, realms of fire and frost and were of the nine realms of Yggdrasil.

It would be criminal not to name the two domains and forgo the chance to make for an awesome yet unintended theme.

"Now, I just need to work on the theoretical frameworks and then flesh out the blueprints."

Thankfully, he wasn't uninspired.

"Time to revisit thermodynamics."

It was a vast field that explored the dynamics of heat and the laws that governed them. If he could find the right law or principle, he could create powerful techniques that harnessed these laws better than anything in this world.

He had already had a large flood of ideas on how to go about creating a domain of heat and cold.

Especially for heat. There were so many possibilities that he would actually have to go through a phase of scientific empiricism with trial and error to gauge which of the many ways. He could rely on friction, acoustic conduction, gaseous convection, and a variety of other principles. He could also choose what sources of energy to convert to heat, be it his own physical power, environmental energy, or even his opponent's power in the most novel cases.

In the case of the cold domain, the options were more limited. It was much easier to generate heat than cold, and the former happened naturally every second. However, perhaps it was for the better. It would not do for him to be overwhelmed by too many choices across the entire board such that just making a choice would take a long time.

And thus began a new training arc that Rui set himself into, excited by the countless possibilities that existed.

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