The Fifth Element (4-in-1)

Knowledge was constantly being updated, and alchemists' understanding of the "Fifth Element" was somewhat like the shift from geocentrism to heliocentrism, or from the simple notion that the sky was round and the earth square to the various Cosmic Models.

The Fifth Element in alchemy, whose original meaning was "the pure essence hidden within all things, as well as the material composing the celestial bodies," literally meant "the fifth essence."

It was the fifth element apart from Earth, Wind, Water, Fire, a subcategory of the Source of Magic Power.

In the Classical Era, it was often believed to be "aether," the material composing the celestial bodies, souls, and the spiritual essence of all Living Beings, filling the void and existing everywhere.

Later spiritual theories gradually overturned this idea, shifting the focus to Mana, the fundamental existence known as the Source of Magic Power.

Then came materials such as stibnite, a type of Star Core associated with the materialization of energy.

Of course, this theory was gradually overturned as well. It was even deleted for a time, being regarded as an imaginary substance that did not exist.

It was not until the Modernist Era, when certain alchemical schools borrowed elements of quantum mechanics from the scientific side, combined them with the Theory of the Four Roots, and clearly established the concept of Source of Magic Power, that it was finally accepted and unified once more.

Thus, the textbook definition was: Earth, Wind, Water, Fire, and the Fifth Element all belonged to the Source of Magic Power.

More specifically, it represented "other things," encompassing incorporeal entities and concepts.

After returning from the technological plane, Roy happened to have read some books and knew that Imaginary Space and Digital Monsters were both products guided by the Holographic Universe Theory.

By combining this "holographic"