To make them seperate from the Planescape system i’d design them around 13 core concepts which don’t fit into the morality/elemental divide

So  they would be 

1) Madness

2) Dreams

3) Fear/Nightmare

4) Truth

5) lies/art

6) Day

7) Night

8) Twilight

9) Thought

10) Magic

11) Knowledge

12) Grief

These creatures are among the most feared in all of the planes, though they are rarely seen by Primes.   Their own domain is nothing more than an endless battlefield of death and destruction, but what makes them scary are their unbelievably huge forces which can be found invading other planes.  Now a giant insectoid army of evolving monsters coming in an endless hoard isn’t exactly…pleasant to consider charging at you, but you know, better than a demon hoard right?  I mean sure they strip mine everything they approach and use their victims to make more, but you know that’s fine right?  Here is the problem, they don’t eat people.  They eat ideas.   Or more specifically, they eat Planes built upon ideas and so while they aren’t a direct threat to the Material Plane, the Hive Fleets are seen as one of the greatest threats in the world to Planes, as the massive Tyranid armies can cause havoc on almost all planes in their never ending quest for resources.  These creatures are infamous for their unique form of reproduction, any time they attack a plane, they can tear bits of the plane itself  off and add it   to these massive “Flesh Vaults” that they carry with the fleets, which they use to create new Tyranids.  Depending on the type of creature they consume, a new type of Tyranid is created, and they can be specialized dramatically.  These creatures are commanded by some sort of Hive Mind, though as far as anyone can tell, it isn’t centralized in any singular location but is rather a larger collective mind (similar to Many of One).  

       So can they actually win?   Nobody actually knows, they are tearing up whole planets worth of various planes but…the planes are infinite so what does that mean.  Well it is doubtful that they could destroy an actual plane but they certainly damage it, and as Planar cartographers are always pointing out, some infinite planes are smaller than others.  So while it is unlikely the Hive could completely destroy a plane, they could reduce it to a much smaller infinite plane (this is the part where mortals normally hit somebody).  However some fear that should they eat enough, the plane itself will completely collapse and have to be remade, which will drastically effect the Outer Planes dramatically.  

   On the Material Plane Tyranids are mostly unknown except when Shavarath is far away , but the occasionally scouting fleet will emerge on the Material Plane to raid for more basic resources.  These hoards will ravage the entire region of the material plane, strip mine all the resources they can grab, and return home. As they cannot use Material Plane resources to reproduce unlike ideas, Tyranids try to avoid the material plane, all losses there are permanent.  However when Shavarath is in alignment, they sometimes come in en mass and try to take over the Material Plane, nobody knows why this is as it doesn’t really benefit them in the long run.  Even weirder though, Tyranids have been known to be randomly nice, Hive Fleets have been known to wander across the Material plane not destroying but repairing the world around them to be livable and improved, creating so called “Eden Worlds”, marvelous realms of extremely alien but beneficial forms of life (ok there is the odd mana monster that eats people, but those are just hungry). These Eden worlds often are a massive source of magical resources, food, and just general usefulness.  Tyranids have even been known to land on the Material Plane and help the locals farm or rebuild their cities, sometimes even creating entirely new cities for mortals to live in.  They never explain their logic or reasoning, they just start working then leave.  In one instance a great ancient city was severely damaged by an earthquake, only for a Hive fleet to emerge and the Tyranids to rebuild the city to its original specifications.  They also have been known to randomly attack major threats to mortals as a whole, such as undead armies or the Blight.  In fact on no less than 8 occasions Demon/Devil/Daemon incursions into the Material Plane were halted by the Tyranids, and once they attempted (and failed) to turn back the Burning Legion.  Nobody knows why they do this, only that the “Eden Fleets” will almost never engage in combat on mortals until they return home, while raiding fleets will almost never rebuild the world until they return home, each flee evidently having a specific task.  

    Currently the Hives are mostly focused on trying to consume the Outlands, because the Divine Realms are too scary, and the Middle Planes are difficult to invade as they are always moving.  The major battle fronts right now they are focused on Bytopia, Arcadia, The Outlands, the Fernia, Gehenna, Abbadon, and somewhat inexplicitly the Blood Rift.   They avoid Arboria however, as that plane has a tendency to eat them, and Avalon seems to confuse their Hive Mind.  Where ever these incursions occur, they strip the entire plane bare, eating all of the natives of Pettioners, and then start taking the plane apart.  The remains of the plane are taken back home to “The Flesh Vats” massive vates of flesh that are fed by ideas and as these planar chucks are put there, new Tryanids emerge.  So invasions pay for themselves and almost every infinite plane has an infestation of these guys somewhere.   Again, nobody is quite sure if what they are doing can work, chucks of planes the size of planets have been destroyed and eaten by these bastards but again…the planes are infinite.  As a rule, natives do not like this and work to get rid of them as quickly as possible, in fact Modrons, Rilmani, Proteans, and Inevitables are so quick to destroy them that most Tryanids don’t even bother, but the good and evil planes are especially at risk.

       The Lower Planes are so distracted by their own affairs that directing their armies at hoards of Tryanids simply doesn’t seem feasible, and they can go for quite a long time before somebody notices them and kills them.  The upper planes however really can’t handle this, they are over stretched and over taxed as it is, and diverting already desperately needed forces to deal with these planar incursions just isn’t in the cards.  They mostly try to divert them off of their plane or destroy their Hive Fleets before they start reproducing, but if they get a hold then they usually try to get good deities handle this, which of course further puts them in debt to the Divine Realms and makes Eblis sad. (Eblis BTW destroyed an entire Hive Fleet by himself when they approached his realm).  Other Upper Planes have had…inventive solutions to the problem.  Bytopia regularly hires Yugoloth armies to handle them, with the hope that both sides destroy each other.  This is a pretty good solution but it means that random adventurers wandering through Bytopia always have to be on guard against a random force of Yugoloths or Tryanids running around.  Arcadia employs Armies of Fairies to keep the hoards at bay, while the Blessed Islands have taken to letting Demonic/Devil incursions unto their territory with the hope of destroying these enemies and each other.  Elysium have taken to creating massive “trap Portals” to teleport the entire Hive Fleet to a different plane, ideally Abbabon (Screw you Devils). Aborea just randomly eats them, and Heaven’s massive oceans normally handle things (though small bands can still be found in the Upper Planes. All of the Upper Planes occasionally employ adventurers to clear out bands that they can’t be bothered with, due to their constantly understaffed fight against evil taking up most of their priorities.  The Lower Planes meanwhile normally just let them eat until they can divert the forces, and then wipe them out in a massive battle that makes any other battle short of the Blood War itself seem like nothing in contrast.  Finally the Tyranids have thoroughly invaded the Realms of both the Jinn and the Elementals, who are fighting massive wars with these fuckers, often unheard of as mortals cannot easily gain access to these planes.  

      As their numbers are absolutely overwhelming, they can keep going for a long time, though even they are somewhat over stretched at the moment.  The Tyranids have only been defeated fully once when they ran right into a Darkspawn hoard, thought that is more of a tie than anything else.  The Darkspawn were eventually wiped out, but due to the Blights unique properties, the Tryanids found that they could use the Darkspawn as a form of reproduction and instead had to retreat empty handed.  It is likely that their invasion of the Blood Rift is going to end equally badly, as impressive as the Hive Fleets are, against the endless conflict of the Blood War they are simply being destroyed.  In fact, their own plane has been counter invaded by armies of Demons and Devils, both of whom were trying to wipe out the Tryanids but have instead become trapped into a fighting each other.  The Tryanids are playing with fire however, as should both sides see them as a true threat, they might unite against them and…well ask the Angels how well that went.  

     The Plane itself is rather simple, the Surface is a massive three way battlefield while the underground is the massive nests of the Tyranids as they work hard to breed more of themselves.  Three Armies (Angels, Demons, Devils) counter attacked the Tyranid forces at the same time and managed to successfully drive them from the surface of their own infinite plane, only to find themselves in conflict with each other.  The Plane is now a major battle for the Blood War, with the Angels pinned down in the middle protecting the Portal to the Radiant Throne, all the while trying to hold off the forces of the Demons and Devils while pitting the two sides against each other. Every so often all three sides will launch attacks on the Swarm, but they inevitably fall to infighting before they can maximize that effect.  The Swarm for their part finds the endless war annoying, but mostly ignore it, when a new Hive Fleet Emerges, it breaks out of the ground dramatically scattering all the combatants while it departs for a new home.  

The Diurnal Planes, also known as the middle planes, are…odd. On the surface they seem like the reductivist simplistic hackneyed version of the Outer Planes, but upon closer examination that isn’t actually true.  The Middle Planes are not like the Outer Planes, just as the Outer are not like the Inner, they are just a different category.  What makes them especially weird is that they aren’t constant, while the Outer Planes serve as the final resting place of souls and the inner planes serve as the material building blocks of creation, the Middle Planes rotate around, moving between Material Worlds effecting them in odd ways. The Middle Planes beings also don’t have as much of an established relationship with each other, no Concord among the Elemental Princes, no Blood War or Unity of Light, they mostly view each other the same way they view everybody else. They aren’t ideological or physical concepts, instead they are embodiments of a different form, of Dreams and Madness, of Thought and Truth, of Knowledge and Memory, of Love and Hope.  Oh and it’s important to remember this, they are pretty much all massive assholes.  

 “The thing you need to understand about the natives of the Diurnal Planes is that….well they are just dicks.  I mean, Demons come in here, eat our children, burn our house downs, and then do the whole torture/rape/eat/kill routine before harvesting our souls for an eternity of suffering in the Abyss, but I can sort of look past that because they are demons, what do you expect?  I mean Demons torture us, Angels fix Old Joe’s barn, and Proteans make us eat Walt Whitman’s poetry, its just what they do, it’s their job.  But when Daelkar skin us alive and force the skin, muscles and bone to fight to the death for the privilege of forgetting that their existence is an anthemia to all that is right in this world, all the while watching our souls be devoured and our minds being turned into carrots, that isn’t because they are magically compelled to be a force of torture and pain. It’s just because they are assholes”- Farmer Wei, survivor Veteran of the Mindrape wars, long time survivor of living in the material plane (He is multitudes)

“I kinda prefer the Daelkar honestly, I mean if you’re going to beat me to death with my own skull, rip my spine out and use it to strangle my belief in a just and rational world to death, I would prefer if you had some fun with it rather than doing it as a job?  At least somebody is having a good time”- Joan the Spineless, hero of the battle of mindfuckery.  

           “It shit like this which makes me hate calendars.”- Little Orphan Juan, justifying not doing his HW.  

      What is important to understand about the natives of these planes is that they feel more like a species rather than an exemplar, in a way you should view these creatures as extradimensional aliens rather than conventional ideologies the way that the Outer Planes beings are, these creatures are mostly just…weird. Also for reasons that aren’t know (But are likely Morte’s fault, like everything else) these creatures despite not being tied to the Lower Planes, tend to be….well assholes.  Of the 14 realms, 9 of the races actively hate you and are trying to kill you at any given moment.  They aren’t doing this out of some sort of ideological commitment to evil, they just kinda are massive dicks.  Even those who aren’t trying to find ways to kill you likely are indifferent or just weird, only the Sharn and the Ancients seem to care about your existence in a way that is healthy.

           What makes these realms even stranger on a cosmic level is that they rotate around the Material Planes, in such a way that they can either be close to the realm and thus cause certain magical effects (Dal Quor being close causes people to dream more intensely and then their dreams to come to life) or far away to have different effects (nobody dreams if Dal Quor is out of Orbit).  All Material Planes save the Avatar World experience these effects, but the world of Ebberon is the hardest hit obviously, being basically designed to be in close contact with these guys.

It is also worth noting that there are only 13 of these planes, the 14th does not exist.  Any attempt to find said 14th plane will fail.  There is no 14th plane.  

Daelkyr Lords of Insanity 

Adaru

Dolgrim

Dolguant

Magia 

Dolghast 

Akleu

Gibbering Mouther and Gibbering Abomination

Gibbering Orb

Gibbering Mouther

Chocker

Dolgrue

Symbionts

Daelkyr Spawn