The Keeper's Stagecoach

Ride in Luxury...

I've only been here a few seconds... or has it been years. Have I been forgotten, or worse, misled? Such thoughts are surely blasphemous. This place, this grand interior makes me wonder. What secrets does it hold for me? Wait...
What is this feeling? I feel confined in this open void. I feel as if my thoughts are all I am, spoken without speaking. They feel scrutinized, as if many eyes scan every thought, but not the one who bears them. My thoughts feel like words on a page... What could this mean? Do I not exist?

— An Acendant Cultist

For The Bearers of Doors and Locks, there is no higher honor, nor greater joy, than to be welcomed into The Garden of Gates and Keys. There's only one way to enter this strange world-between-worlds: The Keepers Stagecoach. Looking as if it was plucked right out of the Victorian era, the stagecoach appears shortly after a wave of thick fog.
When it arrives, the cultists who follow The Keeper of Gates and Keysrejoice, for one of their own is to ascend to a higher state of being. Every time a fog rolls in, the cultists prepare for its arrival. They gather the best and brightest and line them up so the driver can see.
The driver is a strange humanoid figure. He has no discernible features, only pitch black skin shaped around a vaguely human frame. He has seven arms with hands gripping seven reins. The reins stretch out further than the eye can see into the fog. Some drifts low, while others stretch high into the sky as if the coach was pulled by giants.

Ascending

The driver is remarkably picky about who he allows to enter the coach. Anyone who attempts it without approval will be struck down immediately in gruesome fashion. Once an individual is chosen, they will never be seen again. No one knows what makes an individual worthy, and some even consider the choice random to begin with.
According to the scriptures kept by the cult, when want to send that they are taken to The Garden. The keeper or take them on the whimsical journey across reality. They will behold wonders and horrors alike, and when they return to The Garden, they will be given a new form befitting the position they hold in the Keeper's favor. The keeper is said to take the soul on strip it from the Mortal coil, a sack of meat and rags.
Some of these souls are emblazoned in stone, forever decorating the garden and traveling its many paths. The honor that you will have their soul expand beyond comprehension. These souls become singularities in the stars above the garden. They will forever consume and expand, free from death and free from entropy.

The Grand Interior

According to the texts, the inside of a stagecoach is not what you would expect. The inside is vast, an endless cosmic sea. The cultist will see entire universes before them, reality folding and unfolding without reason. They will linger in the void, sat upon the most luxurious leather as they bath in starlight and nebula glow.
They will not leave the couch until it has reached its destination, though it is difficult to determine how long it takes in a place such as The Grand Interior. When they leave the stagecoach they will be met by The Keeper herself, a featureless statue of a woman in flowing robes that move in the wind despite their composition.
It is then, according to the texts, that they are properly evaluated. When their final form is determined, the journey with the keeper will begin. Sadly, the texts neglect to clarify exactly where it is they go.