Denzark
08-31-2011, 03:01 PM
Having considered the question of 'is the Empire dying out' or not, in response to a query on BoLS main about how the Empire always seems to be on the back foot, in this short treatise, I am going to examine each (playable) race in turn, and look at what their racial goal (if any) is, how they aim to achieve it, and is this likely to succeed?
I caveat this as follows (as well as confessing this is mahoosively lengthy, mea culpa...):
Firstly, I will not research or offer any source commentary - I will comment from my own knowledge of the fluff. If people want to offer substantive sourced evidence to the contrary, so be it. Secondly, this may seemed skewed from an Imperial perspective. I will tell you which codexes I own and play, so that you can see what is firsthand knowledge or not. Lastly, all Imperial factions will be grouped under the heading 'The Empire of Man' irrespective if the differing armies have seemingly different aims.
Eldar (Codex owned and played)
The Eldar seem to be all about tragedy and loss, and past glories turned in horror into Slaanesh as a pursuit of sensation went wrong. That being said, their aim seems now to be to endure and keep what is left alive and secure from Slaanesh. I cannot find any evidence that they wish a return to their pre-fall status, nor that they are indeed capable of doing so.
How do they seek to do this? A 3-pronged approach. Firstly, strict adherence to the Eldar way, to govern their passions through strict discipline prevent a further fall. Turning to Khaine in the guise of exarch is the worst example of allowing passions to govern, which is tolerated and channelled into something of use. Secondly, mastery of the Webways and sticking to self contained craftworlds (yes I know about exodite planets but they are on the edge of society) that can withdraw into the Webways and away from the danger or the focus of galactic conflict. Lastly, using every means at their power, psychic, Webways, mastery of fate, to influence events to secure themselves - even sacrificing the lesser races or making them fight each other, as long as they can benefit.
Will they succeed? The endurance since the fall, which was what created the warp storms which allowed intergalactic-travel and thus the expansion of the Empire, has been pretty good. Whilst fallen craftworlds are alluded to, the major and minor ones seem to be surviving successfully - although getting in the path of a Hive Fleet probably doesn't help. Greatest threat? In my opinion, if Ahriman unlocks the key to the Webways, and gets to the Black Library, its game over. However, given Ahriman has not achieved Daemonhood, I reckon this means Tzeentch/Magnus is still p*ssed with him about the Rubric - and also a further fall will strengthen Slaanesh. I don't think Ahriman will succeed without Tzeentch so I think the Eldar will carry on.
Dark Eldar
I've never been sure about these fellas. They seem to be one of the most introspective of races, looking in at the eternal power struggles in Commoragh (sp?) Do the DE want to subjugate the galaxy? I don't think so. If they subjugated everyone, there would be no slave raids to be had, and no further sensations to be had. I think the aim of everyone is individual not racial - probably to eke out a living in Commoragh and for those with the influence and reach, try and be the top dog - replace Vect?
How do they do this? Raids out when necessary, internal raids on DE competition when necessary. Masterful use of Webways. Large scale external raids into another races' empire probably implies only a need for slaves or materiel on a larger scale - not a grand plan.
Can they succeed? I think they are like a hardy and perennial weed. No one is capable of mounting a campaign of full xenocide against them, and as long as they remain a reasonably small scale problem compared to the big boys, I think it will be live and let live, with a spanking where needed, but no one attempting to assault Commoragh. So, they will probably carry on in the same hedonistic fashion forever. I freely confess this is one of my least favourite races that I know not much about, feel free to correct.
Orks (owned Waagh the Orks, Ere we go, Freebooterz, and 2ed codex. Stopped playing after that).
Orks exist for war. It's all about the fight; who is the biggest strongest Ork. Struggle and dominance is all, might is right. If there are no stinkin' humies or bugeyez to stomp, the Orks will happily do each other over. What is the racial goal? To carry on fighting. The Ork outlook is illustrative - if they win, they win, if they die, the opposition can't hurt them and if they run away they can come back and have another go another day. It is impossible to prevail against this mindset; the only way to stop Orks from fighting is to kill all the Orks - an impossibility.
How do they do this? Internecine warfare on Ork held systems, where they fight each other and if they are fortunate, the indigenous hostile life forms who may form good sport for hunting. However, Orks are masters of force field technology and can use this to make a spaceship in almost any state of repair, suitable for travel. This ability to migrate couples with another racial trait - the Waaaagh. Periodically, an Ork will receive messages in his head, that he believes come from the Ork Gods Gork and Mork. He will follow those messages and by force of personality (and brute strength) unify the fighting Ork tribes into a force directed outwards at the nearest alien systems, to conquer and crush all opposition. Luckily for the rest of the galaxy this tends to have a natural saturation point - possibly the fact that an Ork Warboss needs to lead from the front to maintain control means their death is inevitable, and the resulting power struggles in the power vacuum allow the opposition to recover and suppress the now un-unified elements. Whatever, all Waaaagh to date seem to collapse under their own weight. The other option is that the most successful warbosses such as Ghazgkull Mag uruk Thraka have such a high threat index that their opposition will throw everything against them resulting in a hard-stop for the Waaaagh.
Will they succeed? Quite simply, whilst a single Ork remains alive, he will be fighting, and therefore they will have succeeded. Given a spore based reproductive process, it would be well nigh impossible for them not to unless in the face of total extinction - which I contend no race in the galaxy is capable of bringing about.
Tau.
I can't even begin to talk credibly about them. Suffice to say, I don't see them as rampantly expansionist, nor a threat to the Empire of the magnitude of the big three - Chaos, Tyranids, Necrons. Indeed Tau have to deal with these things as well at some point. Sorry to disappoint the Tau enthusiasts, I'll defer to you here.
Necrons (latest (?!) owned and played)
Necrons are quite simple really. The metal bits are the slave race (necrontyr) who serve the psychic beings known as C'tan, as vassals. The aim is the conversion of all living things into psychic energy for consumption by the C'tan. The C'tan aims are quite inscrutable but may be linked to the furtherance of their ancient war with a McGuffin known as the Old Ones. So, kill 'em all - awesome.
How will they do this? At the moment, slowly. Most of the untold millions of Necrons are 'slumbering' on massive tomb worlds - some of which have been unwittingly colonised by younger races. Something unclear has triggered a waking and massive legions slowly fight and kill everything in their way. There seems to be no overarching strategy beyond total conquest.
Can they succeed? Militarily, I have to say, not without setting the big C'tan alarm clock and getting ALL the metal boys into the action with concerted aims. Concentration of force and all that - without this I can see them having localised victories only, but not any serious territorial gains. Also, if the C'tan need life force then they must get a sustainable source - a la The Matrix - so farming rather than destroying sentient life.
Whilst this would imply a need for serious change (stand by next codex) they have one thing in their favour - a mysterious ability to disappear back to some central point when enough of their force is rendered inoperative. This includes all pieces of - no prisoners, not much wreckage for examination. Phase out, their implacable nature, the unknown basis of their technology and the fact they are machines means they have not got the same issues of supplying their forces that other races do - logistically they need nothing more than they have and they disappear and repair and come back if confronted with sufficient force. All living races threaten their aims by resisting, but the very nature of the Necrons, combined with no emotions nor even a beast-like flight or fight reaction, leads me to rate them as one of the top 3 threats facing the Imperium. You literally have to disintegrate or stasis them to stop them coming back at a later time, and I don't think any race could do this.
Tyranids.
Another simple race with a simple goal. Come into galaxy/planetary system/solar system. Subsume all living matter, use the genetic material to adapt to new life forms as needed, leave only a lifeless rock. Rinse and repeat.
How do they do this? I won't go into details about spores and the stages of invasion. All you need to know is that an all-pervasive Hive Mind controls all creatures influencing them to achieve these aims to the disregard of every other consideration. Attack until there is insufficient genetic material left in that part of the hive fleet to continue.
Can they succeed? I can't say Tyranids are anything other than all or nothing. They don't seem to attack a system, get repulsed, and then go away with forces intact. They throw everything in until the entire Hive Fleet in question is successful or dead. Key issues hinted at yet unexplored fully, are how Tyranids adopt some characteristics of races conquered and subsumed. There used to be mentions of Ork/tyranid crosses in early fluff. So what happens if they successfully adapt Geneseed? The Genestealers and their various hybrid stages are examples of relative sentience to the extent of tool use and, although this is mainly not referred to any more, there is scope for thinking, reasoning power behind or in conjunction with the Hive Mind. That said, whilst I think the Tyranids could possibly conquer the Imperium, (hence I rate them as the second greatest threat to the Imperium) I don't think they could conquer all races. Firstly, pure Necrons without flesh would hold no interest for them and could operate on a world stripped bare of all mineral and oxygen by Tyranid attack. Hence I think the Tyranids would ignore them except to defend against attack - I don't know what benefit C'tan would get from the life force of Tyranids but expect the sentience is what they want, not just un-reasoning life - otherwise C'tan would have evolved as vegetarians. Secondly, I don't think Tyranids could prevail against Chaos. As Tyranids destroy planets their power grows. But there would be a point at which if successful, the growth to death rate would result in a death scream the equal of that caused by the fall of the Eldar - presumably contributing to a 5th Chaos God. This, combined with an inability to conquer (probably) the Eye of Terror and (definitely) not the Warp means Tyranids could never truly vanquish Chaos.
Chaos (My main army, World Eaters played since 2ed.)
Chaos is interesting in that it has 2 clear but split goals. Firstly, the non-daemonic elements of the Traitor Legions and any renegades, want the overthrow of the Empire and the total domination of all mankind by themselves. The daemonic element want to overrun the boundaries of warpspace until there is free run between the both - in effect the Warp overtakes reality so Daemons can control literally all existence according to the whims of the 4 Gods. To complicate this some of the non-daemonic servants work to the second aim in order to achieve the first.
Can either be achieved? The first is attempted by 2 means - forcing a way out of the Eye of Terror and into the Empire, or supporting insurrection in the wider Empire but then using the rebels as proxies, or even taking over fully. To date, whilst the Cadian Gate guarding the Eye of Terror has been repeatedly ravaged, it has never fallen. Whilst some elements from within the Eye get out to support or sponsor rebellions, none of those has been more than temporary (in the face of 10000-ish years of Imperial History).
As to eroding the barriers between the Warp and realspace, this relies on encouraging sufficient external persons or un-regulated psykers to hold sufficient rituals to allow a daemon to physically manifest. The more sustained the ritual, the bigger the incursion. However, to date, serious incursions are limited by their distance from the Eye of Terror or actual support - a sufficiently big incursion attracts swift retribution and therefore is suppressed, with daemons being banished. To date no Imperial World in realspace has been converted into a daemonworld and then maintained as such - although the level of incursion may be such that the Imperium feels obliged to totally destroy a planet to deny it to the Arch Enemy.
The Greatest threat to Chaos is the Imperium denying them. However in the face of an apparently weakening Emperor, and beset on all sides, I feel there is a natural point at which the Imperium could no longer defend the Cadian Gate. The only thing preventing the entire contents of the Eye of Terror spilling out in such a circumstance is the lack of unified leadership - Abaddon has not been all that successful to date, but should he maintain control, there is a point beyond which an over-brittle Empire must expire. I rate Chaos as the single greatest threat to the Empire, particularly as half of the threat (the daemons) can exist in warpspace and do not need the logistical constraints of realspace to survive - they would quite happily turn it into the Warp at the drop of a hat.
The Empire of Man (Codex SM, SW and IG owned and played since 2ed until now. GK owned, DH played, WH played).
What does the Empire want? Well as arguably the backdrop to which the game and the universe is played, they have the hardest job. Firstly, survive against all the threats there and stated above. Second, presumably expand. I am not going to break down faction goals.
How do they survive against threats? Using the Astronomican for travel through the Warp, a mix of PDF as initial defence, with IG as the back-up and SM as the ultimate sanction - stand fast SoB where the Ecclisiarchy has an interest. GK when it all goes really Pete Tong. Pure military power. The Cadian Gate against the Chaos threat, the Inq/GK against the Chaos Daemon threat. Conventional military against all other threats as necessary.
But what about expansion? Unlike the Exploratory fleets of the Crusade, this seems to be mainly the purview of sanctioned Rogue Traders who chip around on the edge of Imperial space. Now and again an area marooned by warp storms will become passable and thus the Empire re-conquers that territory if able. Sometimes, power levels and desire of the Council of High Lords of Terra will allow or even compel a new crusade of the ilk of Macharius. Mostly, crusading is internal housekeeping against worlds lost to any threat. Overall, it would seem that more worlds are lost to external threats or exterminatus, than are discovered/conquered/resettled.
Now, I have detailed what I think of as the most significant threats to the Empire as Necrons third, Tyranids second, and Chaos first and foremost. Can the Empire survive against the Necrons? Assuming they don't all rise at once (which to date they are not) yes. Can the Empire survive against the Tyranids? Having defeated 2 out of 3 Hive fleets, and having a massive Inquisitorial cordon in place to allow 2 whole Battlefleets to muster, I would say probably - records (fluff) show only a dozen chapters of marines are involved and this is a drop in the ocean of the usually accepted sum of 1000 chapters. Can the Imperium endure against Chaos? To date it has - every Black Crusade weakens Abaddon's stock of original Legionnaires and even those 9 Legion size formations can only replace so often from the dubious genetic stock in the Eye. The obvious question - can the Empire survive against all 3 at once? Well it is - just. But it is truly the death of 1000 cuts.
What would reverse this? The only thing I can think of would be a leader unifying all the diverse political elements (Admech, Ecclesiarchy, Inquisition etc) with a focus of Grand Universal Strategy similar to the Great Crusade. This will either need a reconstituted Emperor or someone of similar stature - Guilliman in stasis perhaps?
Hopefully this small missive will give some food for thought about who would possibly come out on top - I don't think it points to a defeated Empire by any means - more likely lazy or contradictory fluff points to an Empire whose fate seems inexorable if things carry on how they are.
I caveat this as follows (as well as confessing this is mahoosively lengthy, mea culpa...):
Firstly, I will not research or offer any source commentary - I will comment from my own knowledge of the fluff. If people want to offer substantive sourced evidence to the contrary, so be it. Secondly, this may seemed skewed from an Imperial perspective. I will tell you which codexes I own and play, so that you can see what is firsthand knowledge or not. Lastly, all Imperial factions will be grouped under the heading 'The Empire of Man' irrespective if the differing armies have seemingly different aims.
Eldar (Codex owned and played)
The Eldar seem to be all about tragedy and loss, and past glories turned in horror into Slaanesh as a pursuit of sensation went wrong. That being said, their aim seems now to be to endure and keep what is left alive and secure from Slaanesh. I cannot find any evidence that they wish a return to their pre-fall status, nor that they are indeed capable of doing so.
How do they seek to do this? A 3-pronged approach. Firstly, strict adherence to the Eldar way, to govern their passions through strict discipline prevent a further fall. Turning to Khaine in the guise of exarch is the worst example of allowing passions to govern, which is tolerated and channelled into something of use. Secondly, mastery of the Webways and sticking to self contained craftworlds (yes I know about exodite planets but they are on the edge of society) that can withdraw into the Webways and away from the danger or the focus of galactic conflict. Lastly, using every means at their power, psychic, Webways, mastery of fate, to influence events to secure themselves - even sacrificing the lesser races or making them fight each other, as long as they can benefit.
Will they succeed? The endurance since the fall, which was what created the warp storms which allowed intergalactic-travel and thus the expansion of the Empire, has been pretty good. Whilst fallen craftworlds are alluded to, the major and minor ones seem to be surviving successfully - although getting in the path of a Hive Fleet probably doesn't help. Greatest threat? In my opinion, if Ahriman unlocks the key to the Webways, and gets to the Black Library, its game over. However, given Ahriman has not achieved Daemonhood, I reckon this means Tzeentch/Magnus is still p*ssed with him about the Rubric - and also a further fall will strengthen Slaanesh. I don't think Ahriman will succeed without Tzeentch so I think the Eldar will carry on.
Dark Eldar
I've never been sure about these fellas. They seem to be one of the most introspective of races, looking in at the eternal power struggles in Commoragh (sp?) Do the DE want to subjugate the galaxy? I don't think so. If they subjugated everyone, there would be no slave raids to be had, and no further sensations to be had. I think the aim of everyone is individual not racial - probably to eke out a living in Commoragh and for those with the influence and reach, try and be the top dog - replace Vect?
How do they do this? Raids out when necessary, internal raids on DE competition when necessary. Masterful use of Webways. Large scale external raids into another races' empire probably implies only a need for slaves or materiel on a larger scale - not a grand plan.
Can they succeed? I think they are like a hardy and perennial weed. No one is capable of mounting a campaign of full xenocide against them, and as long as they remain a reasonably small scale problem compared to the big boys, I think it will be live and let live, with a spanking where needed, but no one attempting to assault Commoragh. So, they will probably carry on in the same hedonistic fashion forever. I freely confess this is one of my least favourite races that I know not much about, feel free to correct.
Orks (owned Waagh the Orks, Ere we go, Freebooterz, and 2ed codex. Stopped playing after that).
Orks exist for war. It's all about the fight; who is the biggest strongest Ork. Struggle and dominance is all, might is right. If there are no stinkin' humies or bugeyez to stomp, the Orks will happily do each other over. What is the racial goal? To carry on fighting. The Ork outlook is illustrative - if they win, they win, if they die, the opposition can't hurt them and if they run away they can come back and have another go another day. It is impossible to prevail against this mindset; the only way to stop Orks from fighting is to kill all the Orks - an impossibility.
How do they do this? Internecine warfare on Ork held systems, where they fight each other and if they are fortunate, the indigenous hostile life forms who may form good sport for hunting. However, Orks are masters of force field technology and can use this to make a spaceship in almost any state of repair, suitable for travel. This ability to migrate couples with another racial trait - the Waaaagh. Periodically, an Ork will receive messages in his head, that he believes come from the Ork Gods Gork and Mork. He will follow those messages and by force of personality (and brute strength) unify the fighting Ork tribes into a force directed outwards at the nearest alien systems, to conquer and crush all opposition. Luckily for the rest of the galaxy this tends to have a natural saturation point - possibly the fact that an Ork Warboss needs to lead from the front to maintain control means their death is inevitable, and the resulting power struggles in the power vacuum allow the opposition to recover and suppress the now un-unified elements. Whatever, all Waaaagh to date seem to collapse under their own weight. The other option is that the most successful warbosses such as Ghazgkull Mag uruk Thraka have such a high threat index that their opposition will throw everything against them resulting in a hard-stop for the Waaaagh.
Will they succeed? Quite simply, whilst a single Ork remains alive, he will be fighting, and therefore they will have succeeded. Given a spore based reproductive process, it would be well nigh impossible for them not to unless in the face of total extinction - which I contend no race in the galaxy is capable of bringing about.
Tau.
I can't even begin to talk credibly about them. Suffice to say, I don't see them as rampantly expansionist, nor a threat to the Empire of the magnitude of the big three - Chaos, Tyranids, Necrons. Indeed Tau have to deal with these things as well at some point. Sorry to disappoint the Tau enthusiasts, I'll defer to you here.
Necrons (latest (?!) owned and played)
Necrons are quite simple really. The metal bits are the slave race (necrontyr) who serve the psychic beings known as C'tan, as vassals. The aim is the conversion of all living things into psychic energy for consumption by the C'tan. The C'tan aims are quite inscrutable but may be linked to the furtherance of their ancient war with a McGuffin known as the Old Ones. So, kill 'em all - awesome.
How will they do this? At the moment, slowly. Most of the untold millions of Necrons are 'slumbering' on massive tomb worlds - some of which have been unwittingly colonised by younger races. Something unclear has triggered a waking and massive legions slowly fight and kill everything in their way. There seems to be no overarching strategy beyond total conquest.
Can they succeed? Militarily, I have to say, not without setting the big C'tan alarm clock and getting ALL the metal boys into the action with concerted aims. Concentration of force and all that - without this I can see them having localised victories only, but not any serious territorial gains. Also, if the C'tan need life force then they must get a sustainable source - a la The Matrix - so farming rather than destroying sentient life.
Whilst this would imply a need for serious change (stand by next codex) they have one thing in their favour - a mysterious ability to disappear back to some central point when enough of their force is rendered inoperative. This includes all pieces of - no prisoners, not much wreckage for examination. Phase out, their implacable nature, the unknown basis of their technology and the fact they are machines means they have not got the same issues of supplying their forces that other races do - logistically they need nothing more than they have and they disappear and repair and come back if confronted with sufficient force. All living races threaten their aims by resisting, but the very nature of the Necrons, combined with no emotions nor even a beast-like flight or fight reaction, leads me to rate them as one of the top 3 threats facing the Imperium. You literally have to disintegrate or stasis them to stop them coming back at a later time, and I don't think any race could do this.
Tyranids.
Another simple race with a simple goal. Come into galaxy/planetary system/solar system. Subsume all living matter, use the genetic material to adapt to new life forms as needed, leave only a lifeless rock. Rinse and repeat.
How do they do this? I won't go into details about spores and the stages of invasion. All you need to know is that an all-pervasive Hive Mind controls all creatures influencing them to achieve these aims to the disregard of every other consideration. Attack until there is insufficient genetic material left in that part of the hive fleet to continue.
Can they succeed? I can't say Tyranids are anything other than all or nothing. They don't seem to attack a system, get repulsed, and then go away with forces intact. They throw everything in until the entire Hive Fleet in question is successful or dead. Key issues hinted at yet unexplored fully, are how Tyranids adopt some characteristics of races conquered and subsumed. There used to be mentions of Ork/tyranid crosses in early fluff. So what happens if they successfully adapt Geneseed? The Genestealers and their various hybrid stages are examples of relative sentience to the extent of tool use and, although this is mainly not referred to any more, there is scope for thinking, reasoning power behind or in conjunction with the Hive Mind. That said, whilst I think the Tyranids could possibly conquer the Imperium, (hence I rate them as the second greatest threat to the Imperium) I don't think they could conquer all races. Firstly, pure Necrons without flesh would hold no interest for them and could operate on a world stripped bare of all mineral and oxygen by Tyranid attack. Hence I think the Tyranids would ignore them except to defend against attack - I don't know what benefit C'tan would get from the life force of Tyranids but expect the sentience is what they want, not just un-reasoning life - otherwise C'tan would have evolved as vegetarians. Secondly, I don't think Tyranids could prevail against Chaos. As Tyranids destroy planets their power grows. But there would be a point at which if successful, the growth to death rate would result in a death scream the equal of that caused by the fall of the Eldar - presumably contributing to a 5th Chaos God. This, combined with an inability to conquer (probably) the Eye of Terror and (definitely) not the Warp means Tyranids could never truly vanquish Chaos.
Chaos (My main army, World Eaters played since 2ed.)
Chaos is interesting in that it has 2 clear but split goals. Firstly, the non-daemonic elements of the Traitor Legions and any renegades, want the overthrow of the Empire and the total domination of all mankind by themselves. The daemonic element want to overrun the boundaries of warpspace until there is free run between the both - in effect the Warp overtakes reality so Daemons can control literally all existence according to the whims of the 4 Gods. To complicate this some of the non-daemonic servants work to the second aim in order to achieve the first.
Can either be achieved? The first is attempted by 2 means - forcing a way out of the Eye of Terror and into the Empire, or supporting insurrection in the wider Empire but then using the rebels as proxies, or even taking over fully. To date, whilst the Cadian Gate guarding the Eye of Terror has been repeatedly ravaged, it has never fallen. Whilst some elements from within the Eye get out to support or sponsor rebellions, none of those has been more than temporary (in the face of 10000-ish years of Imperial History).
As to eroding the barriers between the Warp and realspace, this relies on encouraging sufficient external persons or un-regulated psykers to hold sufficient rituals to allow a daemon to physically manifest. The more sustained the ritual, the bigger the incursion. However, to date, serious incursions are limited by their distance from the Eye of Terror or actual support - a sufficiently big incursion attracts swift retribution and therefore is suppressed, with daemons being banished. To date no Imperial World in realspace has been converted into a daemonworld and then maintained as such - although the level of incursion may be such that the Imperium feels obliged to totally destroy a planet to deny it to the Arch Enemy.
The Greatest threat to Chaos is the Imperium denying them. However in the face of an apparently weakening Emperor, and beset on all sides, I feel there is a natural point at which the Imperium could no longer defend the Cadian Gate. The only thing preventing the entire contents of the Eye of Terror spilling out in such a circumstance is the lack of unified leadership - Abaddon has not been all that successful to date, but should he maintain control, there is a point beyond which an over-brittle Empire must expire. I rate Chaos as the single greatest threat to the Empire, particularly as half of the threat (the daemons) can exist in warpspace and do not need the logistical constraints of realspace to survive - they would quite happily turn it into the Warp at the drop of a hat.
The Empire of Man (Codex SM, SW and IG owned and played since 2ed until now. GK owned, DH played, WH played).
What does the Empire want? Well as arguably the backdrop to which the game and the universe is played, they have the hardest job. Firstly, survive against all the threats there and stated above. Second, presumably expand. I am not going to break down faction goals.
How do they survive against threats? Using the Astronomican for travel through the Warp, a mix of PDF as initial defence, with IG as the back-up and SM as the ultimate sanction - stand fast SoB where the Ecclisiarchy has an interest. GK when it all goes really Pete Tong. Pure military power. The Cadian Gate against the Chaos threat, the Inq/GK against the Chaos Daemon threat. Conventional military against all other threats as necessary.
But what about expansion? Unlike the Exploratory fleets of the Crusade, this seems to be mainly the purview of sanctioned Rogue Traders who chip around on the edge of Imperial space. Now and again an area marooned by warp storms will become passable and thus the Empire re-conquers that territory if able. Sometimes, power levels and desire of the Council of High Lords of Terra will allow or even compel a new crusade of the ilk of Macharius. Mostly, crusading is internal housekeeping against worlds lost to any threat. Overall, it would seem that more worlds are lost to external threats or exterminatus, than are discovered/conquered/resettled.
Now, I have detailed what I think of as the most significant threats to the Empire as Necrons third, Tyranids second, and Chaos first and foremost. Can the Empire survive against the Necrons? Assuming they don't all rise at once (which to date they are not) yes. Can the Empire survive against the Tyranids? Having defeated 2 out of 3 Hive fleets, and having a massive Inquisitorial cordon in place to allow 2 whole Battlefleets to muster, I would say probably - records (fluff) show only a dozen chapters of marines are involved and this is a drop in the ocean of the usually accepted sum of 1000 chapters. Can the Imperium endure against Chaos? To date it has - every Black Crusade weakens Abaddon's stock of original Legionnaires and even those 9 Legion size formations can only replace so often from the dubious genetic stock in the Eye. The obvious question - can the Empire survive against all 3 at once? Well it is - just. But it is truly the death of 1000 cuts.
What would reverse this? The only thing I can think of would be a leader unifying all the diverse political elements (Admech, Ecclesiarchy, Inquisition etc) with a focus of Grand Universal Strategy similar to the Great Crusade. This will either need a reconstituted Emperor or someone of similar stature - Guilliman in stasis perhaps?
Hopefully this small missive will give some food for thought about who would possibly come out on top - I don't think it points to a defeated Empire by any means - more likely lazy or contradictory fluff points to an Empire whose fate seems inexorable if things carry on how they are.