The Martial Unity

While Kane fell into deep consideration about how he ought to allocate his time, Rui had far more clarity on what he wanted to spend his time training. There was only one answer under his current circumstances after having spent three years in the Beast Domain.

"Time to expand the Yggdrasil System."

Rui found himself perched atop a mountain on the Mellow Manifold with closed eyes and crossed legs. The calm serenity that overtook him on the outside was in sharp contrast to the maelstrom of thoughts that flashed through his mind.

Domains and monsters.

A match made in heaven.

He had already discovered that one of the weaknesses that monsters had was heavy environmental requirements and, consequently, environmental weaknesses. Unless humans had no specific or particular environmental requirement or weakness of any kind, these beasts were strong specifically because they evolved for given environments.

That didn't mean they couldn't survive outside these environments, but it certainly meant that the opposite configuration of that environment was their version of hell.

Now, this was not particularly a new revelation. Rui knew this before, yet never paid it mind because it never mattered. Not until he met the Elder Tree and inherited its vast knowledge of much of the biosphere. Not until he constructed the Tree of Life that extended to all life in the world beyond just the Elder Tree's knowledge base.

The Tree of Life showed him the path, and the Yggdrasil System could allow him to walk it. He just needed to expand his domains to allow him to create environments closest to what the Tree of Life showed him.

"…But there are limitations to how much I can expand the Yggdrasil System."

He heaved a sigh.

The Tree of Life showed him a unique environment for each creature and species. And considering the number of the latter was in the trillions, he could not possibly create the most antithetical environment for each species.

Thankfully, he had already come up with a stopgap solution for this dilemma. All he needed to do, for now, was create a domain technique that created the most common type of antithetical environment in the Tree of Life. He could create domains that contained the common type of feature that he saw in antithetical environments.

"I can start with temperature-based domains."

An overwhelming majority of antithetical had an element of extreme temperatures.

This was not a random observation.

Temperature was extremely important and decisive in its impact on life. Rui knew that countless species had gone extinct back on Earth throughout its long history due to changes in temperature. There were even laws of biology centered around the relationship between life and temperature.

One such law was Bergmann's Rule.

Bergmann's rule stated that the size of a given organism or species of a given region was inversely proportional to it temperature. Colder places tended to have larger organisms and species, while warmer places tended to have smaller organisms and species.

Rui knew this in two different ways, one through his knowledge and research in his previous life. John Falken published some pretty radical research that suggested that taking into account environmental temperature was the best way for combat sports athletes to adjust their body weight to fight in different weight classes.

Additionally, the enlightenment from the Tree of Life also confirmed Bergmann's Rule as one of the countless patterns that he had extracted from the inheritance of the Elder Tree. That was why Rui was so certain that focusing on temperature-based domains was the best idea.

"If I'm to focus on extreme temperature-based domains then that leaves only two options."

Hot and cold.

Temperature was uni-dimensional, after all. Because it was a uni-variable parameter, Rui needed only to create two domains that focused on the extremities of temperature; hot and cold.

"Ideally, they ought to be a little flexible so I can decide the temperature of the environment."

Yet, when he thought of heat, his mind inadvertently drifted to Sonic Singularity. This domain created an avalanche of sound that converged onto a single point from all directions with equal magnitude such that the vectors canceled each other out, and order melted into chaos, leading to plain old scalar disordered heat. It was acoustic heating.

"That's different." Rui shook his head. "That's more of an attack than an environment. I need an actual environment. Attacks can be avoided."

He recalled how the angel he fought effortlessly dispelled Sonic Singularity before it even reached it.

"Attacks can be avoided or dispelled, but an omnipresent environment? Not so much."

As long as he continued supplying the force needed to ensure it remained that way, it would always come back. Furthermore, if it was truly antithetical, even the effort to fight back would be drastically diminished.

He happily dedicated two technique slots to a domain centered around heat and cold.

He briefly considered adding more domains, but…

"…It's best I focus on quality instead of quantity. These are not actively offensive; thus, I will need passive mastery over them for them for them to truly shine."

He had yet to achieve passive mastery of any of his domain techniques. These were fine so long as they could carry the battle by themselves, but passive environmental domains did not inflict direct damage on their opponents. Thus, he could not tolerate being swamped by them when fighting.

Because of that, he decided to limit himself to only two domains in this training session. The lower the quantity, the higher the degree of mastery, the greater the chance that he could achieve passive mastery over it.

His mastery over domain bending, in general, had reached an extremely high stage. Thus, the possibility of achieving passive mastery was much higher as long as he trained it right from the get-go. Once he achieved that, he would be able to wave his domain while fighting normally without any issue in that regard. The only problem was the fact that he, too, would be subject to them.

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