In many worlds, universes or realities that had created a solution to boundary issues. Most have also needed some sort of why of explaining within laws of why these creatures exist peaceful among the souls that the inner sectors are protecting.
The primordial beings at the beginning of however things are made, have leave a legacies of lifetimes to be reborn over and over. To create enough foundations of ideas to stretch to the end of time.
The many cities of the undead is not a single location nor is the center of any universe a single local. Its that what minds have assumed to believe that there is a centre somewhere. It comforts and stabilizes souls to gravitate to a location to build life from.
These lives interwoven many other things like fate, emotions, memories and legacy. This is essentially what the gods and goddess of most religions are protecting, called the fabric of time and space. Its a chaotic mess to look at with how thread tangle and braid with other parts. It is a long sheet of almost infinite cloth.
A skilled thread maker, weaver or protectors can single out a clump of threads that represents the lives webbed together. The more active a soul is at reaching out to save others, the stronger the weave pattern of that section. One thread is the journey of a soul. Many that have managed to clump together soulless things to become entangled into it.
The more fraying and damaged section are those lives lost of self-beliefs or misguided with any sort wishes. The disconnected ones are what they are called. The threads that gods from all walks of culture try to reach, to save from being totally lost from records of time space. A gods power relies directly to how many lives feel saved by the powers of belief.
Those with selfishness are the most enriched with experience and happiness and are often proud of their afterlife chooses or are happy where they are reborn to.
Occasionally there is those whom reach out by other methods like what legacy they gave to society. Some were simple folks whom weren't people persons but its the gifts they left their children. Some are just name with no story attachments but could have been a church attended until the day they died. More modern types have included how close knitted internet chat rooms are (wow, that isn't a thing anymore) or often you send letters to extended family (we have Facebook now).
What happens when we're gone, really? I know the obvious stuff like funerals and sort out assets from your death will.
(Did someone die around the time I wrote this?)
If you ask me, I think the most scariest truth maybe is that the afterlife isn't what we imagined it. Hell is heaven for some and the other way. These places are not designed or look like what we dream heaven or hell being. Or purgatory or limbo. Anywhere we have dreamed up.
What if being a spirit in experiencing your second version of life is about watching the aftermath that is left from them loosing us.
All that marks us equally is just our soul name among the sea vast pages of categories we made for us to be individuals.
Its up to us to make do with what time we have. Our chooses to label what things are to us. Our impacts. And the ashes left behind.