Volume One: Sai

Prologue: Spatial Theory

In the year 3918 AD, Dr. Max Payne, later known as the "Father of Dimensional Space Theory" but at the time called a "madman," verified the theoretical validity of "dimensional parallelism" and proposed the existence of "parallel spaces." However, this idea was not recognized by the vast majority at the time.

It was not until fifty-five years later, through the efforts of Dr. Max Payne's successors, that the first parallel space was discovered in 3973 AD, prompting all of humanity to gradually realize the feasibility of "dimensional space theory" and the infinite expandability of human space.

By the two-hundredth anniversary of Dr. Max Payne's "dimensional space theory," after countless explorations, humanity had found a total of six extradimensional spaces with life. In keeping with humanity’s humanistic tradition, the space where humans themselves reside has always been called the First Space, while the other six, in order of discovery, are called the Second Space, Third Space, Fourth Space... up to the Seventh Space.

Strictly speaking, the Second Space is not a complete space. When it was first discovered by the Sigluna Space-Time Research Institute, they did not believe they had found a dimensional space, but rather a fault between two spaces, because the Second Space is a planar space. Unlike the First Space, where humans live—composed of burning stars, planets and satellites orbiting stars, interstellar meteors, nebulae, and so on, forming galaxies, which in turn make up the universe—the Second Space only has front and back, left and right, but no up or down, an existence beyond human imagination. Although the actual "up and down" in the Second Space may be hundreds of millions of kilometers apart, compared to the billions of light-years of the four directions, this can be ignored.

The reason it was ultimately considered a dimension is because its environment is so similar to Earth’s: vast, boundless land stretching forever into infinity, with mountains, rivers, and lakes, and ever-changing weather. Although these differ greatly from those on Earth, the sky does not have the sun, moon, or stars, but dazzling energy halos, like rainbows or shattered crystal diamonds, still illuminate the land.

The most astonishing thing is that life exists in this space, and the forms of life are extremely similar to those on Earth. If strictly classified, they can also be divided into animals and plants. However, due to the unique nature of this space, all living beings possess strange abilities, some of which are very powerful, even able to resist advanced firepower weapons. In the third year after the discovery of the Second Space, through intensive searches by human exploration teams and using strictly defined positional measurements, a massive gathering of intelligent life was found 16.7 million kilometers southeast of the entrance to the Second Space. Societies of intelligent life were discovered, and a total of sixteen such gathering places were found. The density of life is much lower than on Earth, but the scale is enormous: the sixteen gathering places together cover more than six billion square kilometers, with over four hundred million individuals of various races.

In the eyes of religious believers, the state of the Second Dimension is akin to the legendary paradise where gods reside, so among the general population, the Second Dimension is called the Celestial Realm.

In 3998, the "Second Dimension Space Protection Act," commonly known as the "Celestial Law," was passed by the Space Administration, prohibiting any disturbance to the native residents of the Celestial Realm for any reason, and forbidding the natives from learning that humans are foreign intruders.

The Third Space is the one humanity finds most incomprehensible. In this space, "time" does not exist at all. After countless studies, scientists have found that life also exists here, but in forms incomprehensible to humans. Because the forms of life are on a different level from human life, effective communication between the two is impossible.

Because of this, the Third Space is called the Chaotic Dimension, and to this day remains the dimension humanity understands the least.

The Fourth Space is where humanity suffered its most painful lesson. This space is similar in form to the First Space where humans reside, but the life forms it nurtures are completely different. In the star system where the entrance to the Fourth Space is located, there are eighty-eight planets. Almost every planet has biological activity, with life thriving to an astonishing degree.