As we hinted at in our pitch videos, souls are A Big Deal in Project Eternity's world. The mortal world has not unlocked all of the secrets of how souls "work" and differing schools of metaphysical philosophy can be found in virtually every culture. What is known is that sapient souls move through an endless cycle of waking life and purgatorial slumber among the gods. Often this slumber lasts for years of "real" time, but occasionally it is brief, with a soul immediately moving on to a new life.
Far from being a flawless process, souls are subject to "fracturing" over generations, transforming in myriad ways, and not quite... working right. Some cultures and individuals place a high value on "strong" souls, souls with a "pure" lineage, "awakened" souls that remember past lives, "traveled" souls that have drifted through the divine realms, or those that co-exist with other souls in one body. However, the opposite is also true, resulting in negative discrimination and sometimes outright violence.
Through a variety of techniques (e.g. martial training, meditation, ritualistic evocation, mortification of the flesh), some individuals are able to draw upon the energy of their soul to accomplish extraordinary feats. These abilities range from the mundanely superhuman to the explosively magical. Having a strong soul seems to make this easier, but sometimes even people with fragmented souls are able to accomplish the extraordinary. The individual's body seems to act as a conduit and battery for this power, drawing in replenishment from seemingly omnipresent "fields" of unbound spiritual energy in the world around them.
Thinkers, spiritualists, and scientists of the world have theorized for thousands of years about the nature and purpose of this process, but others have turned to prayer for answer. Rather than illuminate the presumed higher purpose of this cycle, the gods have obfuscated the truth, at times spreading cosmological lies, pitting believers and empowered chosen agents against each other, and tacitly approving the prejudices of their followers to maintain power.
Whatever the fundamental nature of mortal souls is, the people of the world accept the reality of what they have observed: that all mortal bodies contain perceptible energy bound to the individual, and that once they die, their energy will move forward in the eternal cycle that they are all a part of -- that as far as they know, they have always been a part of.
The cultures of Project Eternity are in a variety of different technological states. Though some remote civilizations are still in the equivalent of Earth's Stone Age or Bronze Age, most large civilizations are in the equivalent of Earth's high or late Middle Ages. The most aggressive and powerful civilizations are in the early stages of what would be our early modern period, technologically, even if they are not culturally undergoing "Renaissance"-style changes.
For most large civilizations, this means that all of the core arms and armor of medieval warfare have reached a high level of development: full suits of articulated plate armor, a variety of military swords, war hammers, polearms, longbows, crossbows, and advanced siege weaponry. Architecturally, these cultures also employ technologies found in Earth's Gothic structures, allowing them to create towering vertical structures.
The most recent technologies seeing use in the world are ocean-going carrack-style ships and black powder firearms (notably absent: the printing press). Cultures with large navies and mercantile traffic are exploring the world, which has led to contact with previously-unknown lands and societies and settlement in new lands. Despite their intense drive, these explorers have been restricted from aggressive long-range exploration by monstrous sea creatures that pose a lethal, seemingly insurmountable threat to even the stoutest, most well-armed ships.
Black powder firearms are of the single-shot wheellock variety. Largely considered complex curiosities, these weapons are not employed extensively by military forces. Their long reload times are considered a liability in battles against foes that are too monstrous to drop with a single volley, foes that fly or move at high speed, and foes that have the power of invisibility. Despite this, some individuals do employ firearms for one specific purpose: close range penetration of the arcane veil, a standard magical defense employed by wizards. The arcane veil is powerful, but it does not react well to the high-velocity projectiles generated by arquebuses and handguns. As a result, more wizards who previously relied on the veil and similar abjurations have turned to traditional armor for additional defense.