It begins long before a funeral; at least, in most cases it does. And in most cases they go easily, without a fight, often wide-eyed and fearful but obedient in their obliviousness. Even though for some this has happened many times before, the soul, still infused with the consciousness of its most recent host, forgets how it was before. Sometimes they fight. But more often than not, they are in such a stupor from the transference of flesh and blood to unrestrained freedom that they do not even recognize what is happening to them until after it has already happened. And even then, after they arrive in the next pane of existence, they tend to wander aimlessly, desperately holding on to what memories they had and attempting to make sense of it all. By then it's too late to go back anyway.
Sometimes they drift away before the collection can even take place. That's when one of the more senior ones are called in; to track them down and pop them on the head to send them into the sweet hereafter. Others, more cognizant ones, actually sneak away. Those ones can be a bit more difficult; one, because they are painfully, shockingly aware of what has happened to them and what will happen to them; and two, because they become further aware that the rules of the living no longer apply when you are not tied to a corporeal host. Gravity and physics become meaningless. Although one would think it would be a nuisance to go after these ones, most reapers view it as a golden opportunity. A chance to travel to the world of the living, hone their tracking skills, but most of all, to hunt some challenging prey. Most reapers have forgotten that they too were once hunted down and the ones they now track will most likely be their comrades tomorrow, or worse, their own usurpers.
But there is something divine, heartbreakingly beautiful in the final outcome of a hunt; the soul funeral, as it were. When the soul is released from this pane of existence into the next, it dematerializes into its purest form; indescribable glowing orbs of light. The soul reapers, for all the fear that surrounds them and that they themselves encourage, are nonetheless awestruck by their own work. To many, this is the worth of a soul reaper; it is this small, short moment of peace that every soul and every soul reaper longs to return to.
Their job completed, the shinigami are obliged to return home. With a turn of the sword, an unseen door appears, infused with light, opening into that dimension that humans can imagine, but few have ever seen and lived to tell. Black butterflies flutter haphazardly around them in greeting, ushering them into that familiar place. The sky is never cloudy in that realm; indeed, there's really not even an atmosphere. There are things that feel like ground, that feel like sky and water; but whether or not they actually exist in a tangible sense is anyone's guess. Whatever the soul society is actually composed of does not matter; even if a soul can't remember ever being there before, it still feels like returning to a childhood home that was almost, but not quite, forgotten. To the soul reaper, it feels more than that; it feels like a piece of their own being and it is worth dying for.
The gates to that other door only open once in awhile, and a shinigami does not have the power to open it. You have to have lived a fairly degenerate life for that to happen. The shinigami do not interfere; there has been an uneasy truce in place since before anyone can remember it ever being agreed to. The shinigami sometimes observe, by accident of course. Casually, they peek from a distance, morbidly interested but embarrassed to admit it. The demons come in different forms; sometimes shapeless, slithering streams of silky black smoke; and sometimes they are strikingly human-like in features, just like the shinigami themselves. But the aura is unmistakable. And the eyes are always jet-black; hollow pools of onyx.
The door to the soul society is dark, but beyond the darkness there is light, overwhelmingly bright. This other door is obscenely large, caressed on either side by skeletal hands that swing the door open and close. The light beyond that door is blackness tinged around the edges with crimson. It could send shivers down a junior shinigami's spine, and at the very least, make a senior shinigami cringe with distaste. There is a smell of putrid waste that emanates from the blackness accompanied by the faint sound of terrified wailings and the agonized groaning of millions.
When those ones come for it, the soul reacts just as any living being would; awash in unabated terror. It's no wonder those souls often run, but what's more puzzling is how often the demons that come for them allow them to run. Shinigami pride themselves on hunting their prey down quickly, performing their duty efficiently and gracefully. Demons seem to enjoy lingering; allowing their prey to wander for days sometimes while the demons leisurely track them down. They allow the souls a small glimmer of hope when there was none to be had all along. The shinigami suppose it is another form of torture, just one of many that the doomed soul will experience for the term of their judgment, however long that may be.
The demons do not believe in accuracy or efficiency; it is not that they are incapable of it, it's just that it's much more satisfying to let a soul writhe in slow suffering. The demons crave the macabre and the more a soul struggles the more they take pleasure in shredding bits of that soul's appendages away. It's what a shinigami would distastefully look down on as messy. To a demon, it's pure art.
The shinigami and the demons do not interact; it's another one of those unspoken rules. It is generally accepted that both have a defined, integral role to play in the management of this world, as odd as that concept may seem. It's not unheard of, however, for a shinigami to feel those black, hollow eyes on his body or to feel the soft caress of shapeless smoke kiss the back of his neck. But as tempting as it is to take a demon up on its offer of challenge, a shinigami, with trained patience, must put aside such desires for the sake of a world free from chaos. It's not known if the two sides ever did fight; if they did, either no one is alive to speak of it or it ended predictably with neither side claiming victory. The two are too evenly matched.
At least, that's what we thought.