Zenáthras is remote from the eight planes that surround it, suspended throughout creation in the great continuum of order and disarray. They stretch from Mechanus at the pole of law to Limbo at the pole of chaos.
Connecting with the planes is a rare event for most of Zenáthras because of the power required to do so and because few patrons will permit their charges to leave the Prime Material. For one thing, doing so cuts off the connection between patron and worshipper, almost certainly leaving them stranded unless precautions are taken.
Because of this, little beyond theory is known of the planes and they remain largely unexplored. Their exact arrangement, their absolute size, the populations of their denizens: all of these are unknown. When people speak of planes as 'eternal' and their inhabitants 'endless in number,' they are indulging in hyperbole of the most fantastical sort, though there is equally little contradicting evidence.
By the will of the Five Crowns—and enforced by their servants, the Aeons—no planar force is permitted to intrude on Zenáthras without express invitation by a resident in the form of summoning. Attempts to do so will be met immediately and harshly with force, the offenders driven back and lain low for their hubris. Even prolonged summoning or creatures being drawn directly to Zenáthras by residents risks Aeon interference and is another reason that the planes are left largely ignored.
Mechanus (Lawful Neutral)
The Clockwork Nirvana; a place of perfect, absolute order enforced by the machine-like Inevitables and maintained by the tireless, dogmatic Modron. It is the set of Kaeshem's power and from his Throne of Gears the God of Law oversees his half of reality.
Arcadia (Lawful Good)
A land of white cities and perfect law, it is the home of the Archons, the holy judges and defenders of sacred law. The innocent find peace here, amidst the great libraries of Arborea and the gentle fields of Bytopia.
Carceri (Lawful Evil)
Rising from the grey wastes of Hades, the massive gaols of the Prison Plane trap countless souls for the eternal, twisted delight of their jailors: the Devils. Chief amongst them are the Nine Hells, the greatest nine of the prisons, each ruled by a cruel and powerful Warden, a Devil-Lord of unimaginable strength. Once Demons, they came to a great civil war with their forebears and have claimed the prisons and their prisoners as Devil property.
Celestia (Neutral Good)
Holy, beautiful, and sublime, the crystal towers of the Angels of Celestia offer true peace at the end of long journeys. Hearts can rest easy in the fields of Elysium while those of valor can share tales in the great feasting halls of Ysgard.
Ethereal Plane (Neutral)
The plane of dreams, where souls travel when they leave the body at night. It is a soft, pearlescent mirror of the world and it is here that the quiet Aeons drift, watching over the Prime and ensuring that the will of their mothers, the Five Crowns, is forever obeyed: that no force of the Divine ever again acts on Zenáthras.
The Prime Material (Neutral)
The sun and the moon and the night sky and the world of Zenáthras, all are the beautiful jewelry of the Prime Material Plane, encased within a singularly tremendous crystal sphere upon whose shell the stars glitter like millions of luminous gems. All of man and the works of man dwell here-in, for their brief time before they flow out into the planes and enrich all of creation by their having been.
Plane of Shadow (Neutral)
Though many scholars call it the plane of nightmares to set it opposite the Ethereal Plane, it is not a place of inherent evil, though the fear of the dark that many mortals share can make it seem sinister. Here, the Psychopomp, the ferrymen of death, wait for the souls of the departed when they leave their body the final time. Each soul is given a guide, that will take it to its final rest in whatever plane its actions and beliefs have earned it.
Acheron (Neutral Evil)
A place of endless war, the battlefields of Acheron are massive, misshapen planetoids of blood-rusted iron that drift forever above the furnace-black planes of Gehenna. On these eternal warzones, the demon-offshoots known as Daemons play with the shifting armies of damned souls and shambling corpses, along with creatures unique to their hideous biomes, such as the savage tribes of goat-men.
The Beastlands (Chaotic Good)
Massive, forested lands devoted wholly to the pursuit of freedom and the harmony of all living things, all manner of animals dwell here, alongside the beast-faced Agathions and the wild, tempestuous Azata.
The Abyss (Chaotic Evil)
Endless and ever-changing, the Abyss is the home of the original Demons, the cast-down Zealarchs of Valjaradan twisted by hatred and magic. They scheme forever to return to the light of Zenáthras and to devour those who had the temerity to defy them. In some black corner of the Abyss lies Pandemonium, where the hideous Demodand breed, the result of Demons attempting to create life.
Limbo (Chaotic Neutral)
The howling, astral madness of the Ever-Changing Chaos is where the enigmatic Proteans frolic and the mad Qlippoth mutter endlessly. Within the waters of the Feasting Sea broods Gwolth the God of Chaos, whose intricate, contrary machinations are ever his own.