On the outer fringes of Entirety, encompassing it all, lies an infinite space known as "There." There is where They reside, but... who exactly are They? How does one become one of Them? Why are They so associated with the Test Reality? Are They really gods? Let's take it one by one!
Who are They?
Contrary to popular belief-
Well, no. Despite knowledge of Them being widespread in the Test Reality and throughout much of the RPverse, Their existence is supposed to be a secret, and it's in fact one of Their rules to try and keep that secret beyond certain people of interest (mostly just the Tested.) Still, it's easy to assume They're gods, when in fact They're anything but. They are less a species and more of a status; beings of all species can be found over There and any given being can in theory become one of Them.
What sets Them apart from other beings is:
1) They are immortal. To become one of Them (more on that later,) one must have already needed to die as being one of Them is an afterlife. They can still be hurt, but if Their body is sufficiently destroyed in any circumstance They'll just awaken back in Limbo and go about Their merry way. Thus They can technically "die," but it doesn't stick.
2) They can alter their Vibe. One's Vibe is basically just, like... the power level(tm) Their soul gives off and signifies where someone lies on the Chain so to speak? Maybe I should do a write-up on that someday?? Point is, They can disguise Their true nature from those who can sense vibes, or They can elevate Their vibe to its highest extent, exploding the minds of lower beings. Like, literally! They can do that!
3) They are capable of traveling between Realities. Maybe an Entirety layout discussion is overdue, but essentially they can hop between different universes/dimensions/what have you with little more than a thought. They can also instantly teleport back There at any given time.
Other than that, They're just like They were before. Same species, same anatomy, same powers, same everything. Of course, plenty of services exist over There so They can change any aspect of themselves that They'd like, but upon becoming one of Them nothing changes beyond those three things.
What's There?
There is where They live. It's said to encapsulate Entirety; think of it like the skin on an apple, except the apple is eternally expanding and thus so too does the skin. As such it's impossible to map out or get a true grasp on the size of. Luckily They can just warp wherever They want over There, so getting to spots of interest isn't much of an issue.
As There is an afterlife for Them, They have unlimited control over the place. Any of Them can create whatever They'd like out of nowhere, allowing Them to easily live out Their ideal afterlife. This means There is quite the diverse place, with any number of biomes, architectural styles, and types of businesses scattered about with zero logic or flow. The sky is a multicolored mess, strange vehicles that resemble hamster balls roll across randomly-placed streets, Chillies - angelic chinchilla things that definitely aren't Prinnies - scurry about trying to maintain things... it's definitely quite a sight!
There is a "main street" that serves as the default arrival location and is the part that directly links to Limbo to allow new arrivals. It's lined with businesses, apartments, and eager tour guides, though it's all overshadowed by a mighty court building where the mighty Judge Truly helps keep Them in line...
...And by that I mean it's mostly just used for random meetings when Judge Truly gets lonely and whenever Arella "accidentally" lets a rando find out about Them and thus Needed(tm) to abduct them and bring them back There to turn into Chillies forever. So it's not really all that mighty. But it's certainly there! Every once in a while a rule will get broken and Judge Truly will get to firmly scold them and maybe through them in jail for a couple days, but it's rare that rules get broken in the first place since They're mostly content to stay up There. They only have a few rules in the first place, anyway:
1) Don't reveal Their existence. Keep everything about Them and There a secret. Anyone who finds out about Them needs to be brought over There for safekeeping and will only be allowed to return home after being mindwiped.
2) Don't interfere with lower beings. Leaving There is acceptable - though begrudgingly so - but if you're caught abusing your powers, leading revolutions, or otherwise seriously impacting the lives of lower beings you're in trouble.
3) Always keep cool shades on your person. Yes this epic random rule from 2008 is still canon fuck you
How do you become one of Them?
No one knows!
Well, to an extent. What is known is that being one of Them is an afterlife. You have to die in order to ever receive the offer. When an "eligible" person dies, they'll find themselves in Limbo regardless of what their typical afterlife destination would be. Just like anyone else, they'll sit in the waiting room, get called up to meet with a Reaper, and the Reaper will look at their existentially-automated paperwork and go "holy FUCK you get to get Promoted!!"
Promotion refers to being converted into one of Them. One can decline Promotion, at which point they'll go on to whatever afterlife they would've normally been slated for. If they're reincarnated, their next life is not automatically eligible to become one of Them, suggesting that eligibility is not some quality innate to one's soul.
If one accepts their Promotion, they're brought to a special room and left alone. No one really knows what happens from there. The Reapers that lead you there have no idea, you have no idea, and even They have no idea, since no one really remembers what happens in there. No sound comes out, no one senses any weird vibes, you just walk in and walk out five minutes later with the realization that, hey, you're a divine entity now! Sort of!
Upon being Promoted, one is allowed a Request. A Request is essentially a wish; the newly-Promoted, uh, Them, can wish for anything and have it come true with seemingly no limit. This Request is possible of warping reality, and one could theoretically bend the entire universe to their whims if they so chose. The only thing keeping one from doing so is... well, the sort of person who'd wish for such a thing never seems to end up getting a Promotion, which is about the only lead anyone has on what makes one eligible.
That's sort of a big thing: despite efforts on Their part, no one's been able to figure out what specifically makes one eligible for Promotion. Reapers just see a little note on your Existential Death Paperwork(tm) saying you get to be one of Them and that's that. Hundreds of lists have been compiled over the years claiming to be the right list of traits, but not all of Them fit into any given list. Species doesn't seem to play any role, both horrible people and practical saints have been Promoted, mortals and deities alike have managed to become one of Them, heroes with centuries of accomplishments behind them and little kids who can barely read seem to be treated with equal gravitas... there's no logical pattern, it seems. Eligibility may well be random as far as anyone can tell.
But what about the Competition?
The Competition is the only known exception to typical Promotion rules, thanks to a certain Request. Upon dying in her home reality and receiving her Promotion, a woman named Opine Frazil used her Request to "make the perfect game." This has proven to be a thorn in everyone's side, as Opine never seems satisfied and thus none of her "games" are ever perfect, allowing her to continue warping reality to host more and more Competitions, dragging more Realities into it and threatening Their secrecy.
...That's not the important part, though, what's relevant is that one of her guidelines for the "perfect game" is that any winners of the Competition must be offered a Promotion. How can any game be perfect without the ability to ascend to godhood if you win, right? As such, Opine is capable of theoretically creating an infinite number of Them should she continue hosting Competitions, bringing in new people, and never feeling the end result meets her high standards. Provided the winner accepts, anyway; like anyone else the Tested are capable of declining a Promotion.
Additionally just like anyone else, the Tested are capable of being eligible for Promotion outside of winning the Competition. Oress Holder Poice, for instance, died about midway through the Competition, but he was offered (and accepted) a Promotion anyway.
As the creation of one of Them, the Test Reality is a weird exception to Their rules. All of the Tested are aware of Their existence, and They're free to come and go. The Competition can even be viewed from any given TV up There! They aren't allowed to interfere with the direct progress of the Competition, though, lest Opine boot them out and have the Entirety-warping temper tantrum the rest of Them fear is inevitable, but it's not uncommon for Them to pop in mid-bloodbath to observe.
Needless to say this makes life as a Tested pretty weird, as they live their lives aware that these ultimate higher beings exist and are (supposedly) the top dogs of Entirety. This makes them completely nonchalant toward gods whenever they end up elsewhere in Entirety or when some unfortunate deity gets dragged into a Competition, since they're pretty used to Them wandering around and chatting them up like it's completely normal. The Tested also have to be reminded to not mention Them at all while they're out in the RPverse, since they're supposed to be the only lower beings aware of Their existence.
Of course, at this point it's almost a moot point. Competitions have been held in the RPverse so many times that a broad variety of beings are now aware of Them, and since Opine's Request has yet to be fulfilled it seems the problem will only continue to grow and grow unless someone finds a way to either appease her or stop her...
In theory it shouldn't be a big deal, since They're perfectly safe over There and can just avoid descending into lower planes should there be some great outcry against Their existence, but would it really be a good idea for all of the gods and conquerors and other higher beings in Entirety to realize they're much lower on the Chain than they actually believed? No way of knowing how it'd turn out, but They'd rather not find out.