I wanted to ask a question about the Horus Heresy Fluff. I see that many of the Legions were quite large during the Horus Heresy. I got the impression that the Ultramarines were the largest with about 250,000 marines, and the Thousand sons were the smallest at about 6,000. This was at the height of the great crusade.

How many were left afterwards.

The reason I ask is that the casualties must have been huge on both sides. We have a clue with the Loyalist marines since the number of chapters they spawned would indicate how many were left (every chapter had 1,000 marines). I read some sources that some chapters like the Salamanders were so devastated that they could not create a 2nd founding chapter. I believe that the Ultramarines spawned about 23 chapters which indicate that they must have numbered 24,000 by the end of the war, suggesting a casualty rate of about 90%.

In addition, I see that many of the legions had great companies that had about 1,000 marines each. Some of the legions were in the tens of thousands, but many of the traitor legions broke away and scattered after the final battle. I recall the the Space Marines Battle Book "Seige of Castlax" indicated that the once mighty company of Iron Warriors had barely 67 left when the book begins. I also remember that the number of Thousand sons was about 720 at the end of "thousand sons"

Is there any fluff suggesting how many of the ancient space marines might have survived to live in the 41st Millenium?

Thats gonna be difficult. One way we can determine is looking at the Second Founding and compare that to the size of a codex chapter (average 1.000 marines).

The space wolves suffred heavy casualty during the heresy so they could only muster one second founding chapter.

Space wolves legion= space wolves chapter and wolf brothers chapter. that would put the surviving spacewolves at roughly 2000 marines a decade after the heresy.

You can work out the rest for yourself.

http://warhammer40k.wikia.com/wiki/Second_Founding

http://wh40k.lexicanum.com/wiki/Founding

Concerning the traitor legions i have no clue.

Especialy since we'll never find out the exact number of alpha legionaires...

I also recall reading that about 60% of all space marines descend from the ultramarines so they very well could have been the majority of the second founding at 23 chapters.

About the Ultramarines and their Successors.

At the beginning of 40k, the canon stated that there were around 25k of UM, and they were the largest Legion. They suffered allmost no casualities during the HH, since they didn't really take part in this fight (they were, err, busy or something like that). After a while GW realised how riddiculous that number was, and they increased the number of Astartes in each legion ten times (so there were actually 60k Thusand Sons). Due to this UM went from 25k to 250k, and along with that we can safely assume that the number of successors they spawned increased to something like 240

I thought they edited to be that UM took massive casualties at Calth so even though they started at 250k, they finished much lower.

As for being busy, originally it was that they were deployed far out of position so that they couldn't get back and help prior to the seige on earth...but having just finished Fear to Tread we have Guilliman meeting Sanguinius so----- reasons.

Remember, that the chaos space marines can still make new marines out in the eye of terror so even as you kill them more can come to take their place.

Can you really call it an edit or a change, if the franchise doesn't have a canon ? It could just be two different sources suggesting two different interpretations.

The 1000 Marines per Chapter is something that I don't even think the Ultrasmurfs and their successors really hold to extremely closely.

Especially if the 1000 includes the trainees. It just takes too long to grow a new Marine for them to be quite that limited, and when you include the failure rate? They have to be training a whole lot of new Marines at a time.

I tend to interpret it more as a limit of 1000 Marines deployed in operations away from the Chapter's strongholds (not including those seconded to the Deathwatch), and most of the rest are engaged in training new Marines, recovering from injuries, and garrisonning the Chapter's Strongholds/vital infrastructure. A lot of those not deployed (or recovering from injuries) are probably going to be tech-marines. Not including trainees, probably another few hundred.

Those Chapters that hold tightly to the Codex probably spin off a new Chapter periodically if they haven't taken too many casualties lately.

Ah, now that is something where personally I like to stick with the Codex fluff. Whether it's viable or not depends a lot on how you interpret their activity, though - meaning, how often they actually leave their Fortress-Monastery and go to war, and how many casualties they incur on average when doing so.

That being said, the 100-size of the Scout Company is said to be more of a "suggestion" even in GW's material. Some Chapters have more and still count as Codex-compliant, whereas others who suffer more casualties or failures simply have to adapt with increased recruitment rates and greater mobility between their ranks.

Interestingly, the Index Astartes mentions the Blood Angels recruiting new aspirants only "once every generation", and out of those recruits only 30 or so actually manage to become Neophytes. Then again, the Blood Angels have a longer biological lifespan than the average Space Marine, and the term "once every generation" is, in itself, open to interpretation, considering how short the normal lifespan of Baal's miserable population is said to be.

Needless to say, this would make the Marines a far more limited, precious and, on average, usually understrength resource of the Imperial war machinery, but personally I think this fits neatly into the overall setting. Few would be able to spawn Successor Chapters themselves in this condition - but then again, in GW's fluff this ability is reserved for the Adepts of Earth and their monopoly on tithed Astartes geneseed, anyways. Marines "breeding" uncontrollably is something the High Lords probably want to avoid after the Heresy, and a major cause for the Codex Astartes in the first place.

It doesn't matter how 'freely' Marines make more Marines - there are never going to be enough to go around. A Thousand Chapters of a Thousand Marines is not enough. They're always understrength, and they're nearly always going to be deployed to the hottest spots.

Look at how vast the Imperium is and how slowly its forces can reposition themselves. Consider that within the Imperium the Marines are basically the first responders much of the time. They're the tip of the Imperium's spear, as often as not simply buying time for the rest of the Imperium to react. When the Imperium launches an offensive beyond its borders, the Marines are also the tip of the spear, opening a wedge for the Navy and the Guard to exploit, but if the Navy and Guard can't follow through quickly enough, the Marines can easily be overextended and cut off from Imperial support.

Casualty rates for deployed Marines will vary based on threat levels, but for every easy fight there's a hard one, or more probably, several hard ones. For every weak opponent there will be a strong one, or more probably several strong ones.

Say that on average, probably 10% of all deployed Marines become casualties every year, if not more. Say half of them are recoverable. That's still an average loss of 50 Marines per strict Codex Chapter per year. To fully replace average losses, that's 50 new Marines per year, if, on average, only 1 in 10 candidates successfully become a Marine, that's 500 trainees, and call it about a company of trainers, evaluators, monitors, etc. for one year's worth of new Marines. Figure it takes ~5 years to fully go from human to new Marine these days, and you're looking at about half a Codex Chapter tied up in training new Marines at a time. If a Chapter goes a couple decades with signficantly below average losses (unlikely, true), it'll have grown enough new Marines for a new successor Chapter, and will need to make deals to equip it appropriately, or, perhaps more likely, keep its mouth shut about its over-Codex strength, and simply will send extra marines to family chapters that have recently taken heavy losses, and/or to the Deathwatch.

I certainly subscribe to the notion of the Space Marines being "first responders" or "fire fighters" ... in areas where their reach extends. At the same time, however, I would expect the majority of these missions to result in very few actual casualties, given that Space Marines are experts at deploying in a manner that hits the enemy at their weak spot and maximises their own effectiveness, and that the mixture of Astartes physiology and hi-tech medical support would in many cases allow to "salvage" a warrior in spite of grievous injury.

The vast majority of said missions would also involve utterly outmatched foes such as some pirate band or alien mercenaries who are bound to run as soon as that Strike Cruiser drops into realspace. Speaking of, we probably also shouldn't forget that travel through the Warp alone can twist those numbers a lot.

Sure, every once in a while you may run into an incident where entire companies worth of Space Marines get wasted - usually the result of some tactical error or underestimating the opponent - but even then the Chapter Master always has the option to simply sit and wait in the Fortress Monastery until he is comfortable with the Scout Company's strength.

Due to the way it is organised, a Space Marine Chapter remains fully operational for as long as there is sufficient personnel to bring Companies 1-5 to minimum strength. Replacements for the Battle and Reserve Companies are available immediately, given how they can be promoted straight out of the Reserves and Scouts respectively, so it is really just a matter of how much of a "safety net" the Chapter Master wishes to preserve for truly dark days.

The Space Marines are notoriously independent, and a Chapter Master can always say "no" when called on to send forces in spite of official obligations. In fact, the Witch Hunter Codex included a battle narrative for specifically this scenario.

One could argue that a Chapter's limited ability to suffer casualties is very much intentional, given the purpose of the Codex Astartes in the first place: to curb the power of the Space Marines, and thus reduce the risks associated with a potential second uprising.

If you look at the Ultramarines' organisation in WD #300 and the 3rd and 5th Edition Codex, most of the Companies tend to hang around in the Fortress Monastery most of the time, anyways, keeping themselves busy with drill, training or various ceremonial functions (the daily life of a Space Marine is also explained in the 3E 'dex). It's not like the entire Chapter is constantly on the move seeking glorious battle. Well, with exception of the Black Templars - but those do indeed "cheat" with their numbers, so I'd say it works out.

That said:

Some chapters are "over" strenght, the black templars are rumoured to be double/almost triple of the standard 1000 marines, but spread out over various crusades. The Exorsists have two scout compagnies becuase they tend to go trough recruits at an alarming rate.

I also think I noticed a disparity with the 1000 man per chapter when looking over the force organization of some chapters. They don't seem to count crew in vehicles. It's 1000 marines fighting as tactical, assault and devestator.

But, as mentioned "there is no fluff". Let's be honest, leave a bit of it up to each individual, it's already like this is every major franchise i know of. Star Wars? There are some different interpetations there, same with D&D's Forgotten Realms. Even Star Trek mixes stuff up when the people behind the scenes change and give their interpetation of the fictional universe.

Also, I do believe it's been mentioned that all fluff is written as viewed by the people inside the universe, which i feel adds lots of possiblites into the fluff.

Spoilers for those who haven't read The Word Bearers Omnibus:

That disparity (at least in Codex-adherents) might be related to the fact that when Guilliman wrote the Codex the Legions (and the immediate breakdown in Chapters) were not using Marines to operate most of their vehicles - they were being operated by non-Astartes members of the Legion/Chapter.

Nowadays, instead of having all the Marines deploy as Marines, they've got lots tied up operating vehicles and support elements that could be run by appropriately trained/skilled humans. Fortunately, they still have human crews operating their ships.

I also think I noticed a disparity with the 1000 man per chapter when looking over the force organization of some chapters. They don't seem to count crew in vehicles. It's 1000 marines fighting as tactical, assault and devestator.

That's no mistake from GW. Codex fluff notes that Marines are cross-trained to operate any weapon and any vehicle at the Chapter's disposal in order to maximise their tactical flexibility. This is where all the training and experience goes, and it simultaneously makes every single Marine both more (as he represents a greater mass of education) and less (as he is more easily replaced by another Battle-Brother) valuable.

It's an elegant way to circumvent the problems arising from the hard cap of 1,000 warriors, as it means the Chapter can at least tailor the distribution of said 1,000 warriors to a specific mission or set of assignments, all depending on what you need on the ground. You're fine with all-infantry? Cool, have at it. How about an armoured assault? Call over some guys from the Reserve Companies to man a bunch of tanks. It's mix-and-match!

Some people may also flat-out dislike the idea that the Marines have no specialists to crew the vehicles like modern militaries do. In that case, the "no canon" clause applies and everyone may feel free to make up their own stuff. *shrug*

Didn't the Ultramarines have a Antaro Chronus; a special character that was a tank commander?

The Space wolves only spawned one second founding chapter because their genetic material is not stable and they give exactly zero ducks about being codex complaint.

Really though, there is no definitive list of second founding chapters, GW always leaves the fluff open because half the fun has always been making stuff up as you go, which makes it kind of hard to know exactly how many marines there were after all was said and done. Add to that, GW has never had a good grasp of scale when it comes to battles. You have single regiments of imperial guard taking planets in the the fluff, 100 space marines holding off millions of orks, then you turn around and small batches of tyranids will rip up terminators like they are paper. While the 1000 marines in a chapter works well because as a player you can make your own chapter and build parts of it, and eventually have a whole chapter, the idea that 100 space marines on a strike cruiser, roam the galaxy dropping into battlezones and actually making a difference is pretty silly. (Especially when the conflicts they drop into at times involve millions of Imperial guard and enemies).

The original goal for all the primarchs was to have hundreds of thousands of marines in their Legions. Some were more successful in recruiting than others, and the loyalist chapters caught at Istavaan (Never spell that right, I don't think) were utterly devastated.

As for Chaos forces, I don't think I've ever found a good explanation for how many there were after, but then it rubs me so many shades of wrong that after 10,000 years any of them are still combat effective. Constant warfare in the Eye, against the Imperium and against xenos, take the earlier statement about 100 marines being kind of a silly force multiplier, and suddenly a warband of 40 dudes is supposed to scare me?

Didn't the Ultramarines have a Antaro Chronus; a special character that was a tank commander?

Right, it was Chronus, not Telion! Fixed it in the previous post; thanks for pointing that out.

Add to that, GW has never had a good grasp of scale when it comes to battles. You have single regiments of imperial guard taking planets in the the fluff, 100 space marines holding off millions of orks, then you turn around and small batches of tyranids will rip up terminators like they are paper. While the 1000 marines in a chapter works well because as a player you can make your own chapter and build parts of it, and eventually have a whole chapter, the idea that 100 space marines on a strike cruiser, roam the galaxy dropping into battlezones and actually making a difference is pretty silly. (Especially when the conflicts they drop into at times involve millions of Imperial guard and enemies).

I actually think GW catches too much flak for this. Partially because some fans misinterpret the role of the Space Marines, and partially because outsourced material creates expectations that do not line up with GW's original idea.

I have yet to hear of an example in actual GW fluff (meaning, codices or White Dwarf) where a hundred Marines actually really do hold off "millions of Orks" (though I can provide examples for a thousand Space Marines getting pwned by much fewer Orks), and when the Imperial Guard invades a planet this is usually accompanied by incredibly destructive orbital bombardment, greatly disturbing the defenders' efforts to counter that one regiment (though most often it is actually a battlegroup created from several regiments), or the target world is quite simply unable to withstand the firepower of said regiment (for example a single regiment of Cadians with their modern equipment being perfectly sufficient to eradicate the feral natives of the Sons of Malice's former homeworld).

And as for a hundred Marines on a strike cruiser making a difference - that comes quite simply from their newly dictated rule as a supporting element for the Imperial Guard. The codex reformation broke up the Legions with the specific intent to remove the Astartes' ability to wage devastating wars on their own, and so it should not come to a surprise when GW portrays them as a "force multiplier" for the IG rather than legions conquering worlds on their own. That is, quite simply, the task of the Imperial Guard, even though some fans may prefer to cling to the image of Marines as the movers and shakers in the galaxy when, as far as GW fluff is concerned, it'd be more correct to say they are a remnant . And in a way, that is grimdark all by itself.

The Space Marines are a potent force, and they are best used when striking strategically important locations to make it easier for the masses of the Imperial Guard to pursue their campaign. In a way, you could say that it is Space Marines who win the battles, but the Guardsmen who win the wars, though this is obviously an oversimplification of the awe-inspiring martial efficiency that can be born from those instances when the Astartes and the Guard really do work in tandem and combine their strengths to the best effect. You don't need millions or even thousands of Space Marines to affect the outcome of an entire campaign. Just a few squads, expertly deployed, can affect a campaign in a way that can save the lives of hundreds or thousands of Guardsmen, thus preserving the regiment's fighting strength for future engagements!

As such, it is in a way ironic that I find that all the things GW tends to get accused of have actually often already been dealt with - it's just that people aren't aware of those sources, as this less glamorous and less epic portrayal of the Marines isn't as popular, and thus sees less repetition both in official material as well as amongst the fans, many of whom often tend to focus on Black Library novel heroics when it comes to debating the Astartes' supposed capabilities.

The biggest multiplier space marines can be is just that *space* *marines* as in the fighting force deployed by the navy. Not many ships can survive a boarding action of astartes inside the ship. Ship defense forces tend not to have too much armor penetration to avoid damaging the ship so suddenly having to face an armored foe greatly disadvantages them.

Yeah, that was mentioned in the Battlefleet Gothic fluff as well. Marine ships lack the firepower of the Navy ... but they've got the armour and speed to get close enough for a boarding action, and then you're in trouble!