Chthonic
Chthonic describes deities and spirits associated with the "underworld," or the Lower Planes of Existence, which are characterized by an overwhelming intensity of malevolence. While traditionally described as "evil" or "chaotic," a more accurate understanding recognizes the chthonic realm as one governed by an ideology of dark, infernal hatred and unrelenting resentment. This realm embodies a philosophy of corruption, torment and rebellion against all that is virtuous or orderly.
The common depiction of the chthonic tradition involves the eternal torment of wicked souls in an afterlife of unending suffering. However, the greater aim of the chthonic beings extends beyond punishing the sinful; they seek to bring the same torment upon the virtuous, corrupting the very essence of righteousness. The narrow boundary separating the lower planes from the Prime Material plane, as well as from the Upper Planes of Existence, demands constant vigilance from the forces of righteousness. Without such vigilance, the chthonic powers may one day overrun the mortal world, subjecting it to their malevolent designs and leaving the virtuous planes vulnerable.
Power
The power of the chthonic realm is as immutable as it is formidable. The substance of the chthonic universe and its inhabitants cannot be destroyed or subdued. Their power rivals that of the Apollonian realm, the embodiment of decency, righteousness and order. The balance between these opposing forces is sustained by the center: the living beings of the Prime Material plane. Mortal belief, manifested through religion and faith, fuels both sides of this eternal struggle, empowering either the chthonic or the apollonian forces, depending on the direction of that belief.
Mortals in the Prime Material may draw power as easily from the chthonic as from the apollonian. However, should enough beings seek strength from the chthonic, they risk opening the gates of the underworld, collapsing the mortal realm into a state of torment. In such a scenario, the chthonic forces would establish their new line of siege at the gates of the upper planes, where the righteous would be forced to resist from an even weaker position.
There will always be individuals willing to trade the world for personal power and the chthonic beings eagerly await such mortals. These infernal entities readily grant power, knowing that one day they will consume the very souls they have corrupted. Their offers are enticing, often greater and more immediate than what the apollonian forces can provide. Each small victory by the chthonic realm further weakens its opposition and even the chaotic and self-destructive nature of the underworld may eventually lead to a moment when the chains binding its denizens are shattered, unleashing untold devastation.
Dweomercraft
Communication with the chthonic realm is facilitated through the sage study of Dweomercraft. This knowledge empowers player characters to interact with the dark forces of the lower planes, either to engage in alliances with them or to develop the means to resist their influence. The lore of dweomercraft, like the chthonic beings themselves, cannot be destroyed, no matter how many attempts are made to eradicate it.
Dweomercraft provides characters with the tools to pursue paths of malice and profanity, should they choose to align themselves with the underworld. It also offers a means of understanding and opposing the powers of the chthonic realm, enabling mortals to thwart the dark forces that seek to corrupt and destroy. For those who delve into dweomercraft, the risk is ever-present, as the pursuit of such forbidden knowledge can itself lead to corruption.
Creatures Known to Be Chthonic
This list remains partial and subject to expansion.
See also,
Bestiary
Outer Planes of Existence