Things like coffins existed in almost every civilization that had the custom of "collecting corpses." Humanoid beings often developed such cultures independently.
Even Europe and Asia, two continents with virtually no contact, had independently developed "coffins." The reason was quite simple.
It was because the Netherworld truly existed, and because coffins served as a means of communicating with it.
In a sense, this also counted as a form of "sacrifice." It was one of the operating laws of this universe. The Netherworld truly existed, and the dead really could be reincarnated.
Therefore, many things related to the dead could be explored and discovered. Just as one could discover the existence of the four fundamental forces, certain individuals with particularly keen intuition could sense the special effects produced by funerals, coffins, and similar things.
And at this very moment, at the North Pole of this mysterious planet, there was actually a coffin.
That was truly beyond all reason.
Clearly, this planet was still in the Hadean Eon, the stage when a planet had just formed and was gradually cooling and solidifying from a blazing ball of magma.
It took hundreds of millions of years for a primordial planet to gradually cool and solidify from a scorching magma sphere, then slowly develop primitive oceans, an atmosphere, and land.
During this process, geological activity would be extremely violent. Volcanoes erupted everywhere, all kinds of greenhouse gases blanketed the planet like quilts, lava flowed in every direction, fierce turbulence arose between new strata and the mantle cycle, and earthquakes were as commonplace as eating meals, happening every day.
A planet like this obviously had no life.
Actually, that was not entirely true. The Boundless Tribe had once seen a special form of life called "demons" on other Hadean planets. They possessed no biological characteristics