My Teacher Is Way Too Strong!

Lu Xingshen felt a little uncomfortable at the moment.

According to what the Green-skinned Big Guys and Kentji had said, that Orc Sword Saint had been someone from nearly three hundred years ago, and the time when he had been active in the Main World and various planes had been even earlier.

So the one beside him now...

Conservatively estimated, he was three hundred years old??? What kind of goddamn immortal world was this? Back on Earth, creatures that could live that long had still existed over a thousand years ago, probably around the late Tang Dynasty.

After that,

the Spirit Energy environment around Earth gradually weakened... Creatures capable of living that long gradually became unable to adapt to Earth's environment. They either weakened and were killed, or fled from the place.

But for a long time afterward,

the constant movement of the Solar System and the Milky Way Galaxy through the universe caused some different subspaces to connect to Earth's coordinates.

That was what led to the later invasions by other species,

and Earth's establishment of the Unified Administration Bureau.

But here...

the spirit energy environment seemed to have always been this rich?

Of course not.

The Main World's persistent pursuit of planar colonization over the years was not for enslaving populations, but for building the "Spirit Energy Tide Great Circulation"! Even before the Magic Empire, mages had used the Mage Towers they continuously established to observe that the spirit energy environment across vast regions of the Main World fluctuated like tides. After hundreds or even thousands of years of data analysis, they had further confirmed that—perhaps one day in the future—the Main World would also face spirit energy depletion!

For that reason!

Even before the Magic Empire, mages had already raised the question of "how to deal with