Check the tyranid codex. It says that the troops on Macragge (which were lead by space marines, but included the entire planetary army and titans) were only able to "hold them off" until the imperial navy came to the rescue and destroyed the hive fleet. But knowing how arrogant the marines are, it wouldn't surprise me that they tried to claim all the credit for the victory, especially since the battle took place on their home turf. Think about it, one company of marines holding off the entire hive fleet doesn't even make sense. That's only 100 people. Even if each marine is guarding an entire square mile, that still means that the tyranids will have free range over 99.999999% of the planet. Heck, even an entire chapter holding a planet against a hive fleet doesn't make any sense. With only 1000 people, they could slaughter tyranids all day every day and probably wouldn't even be able to kill them faster than they reproduced.
Do remember how crappy the imperial armies are. Their soldiers would get annihalated by the tyranids. They would really only help as cannon fodder. They are for situations which are too unimportant for space marines.
Most planets have their own planetary army for home defense. The best of those forces go into the imperial guard. So in general, planetary armies aren't as good as the IG. You are correct that it wasn't the IG fighting on Macragree, it were merely the planetary army plus a Titan legion and some space marines. It doesn't matter how good they are; they can only be in one place at a time. There were over 1000 ships in the hive fleet and many millions of individual tyranids. The idea of 100 soldiers defending an entire planet by themselves is just laughable. According to the tyranid codex, they won because they had help from the entire planetary army plus a titan legion, and because the imperial navy arrived in time to destroy the hive fleet before they could be overrun. The strategy would be more along time lines of trenches lined with heavy bolters, mortars, artillery, tanks, etc. While they're far away pound the swarm with artillery, when they get closer use tanks and mortars, then when they get really close switch to heavy bolters etc. Then you get eaten, and the tyranids are off to the next defensive line. There are a billion planets in the imperium, and only about 1000 space marine chapters at 1000 marines each. On the other hand, each world usually has a single active IG regiment of 5-6 thousand troops. This means that there are about a thousand IG regiments and 5-6 million IG combat troops for each individual space marine soldier. I'll leave it to you to decide which force is more important.
Okay, i dont have time to argue more than one point. But in reality there are millions of space marine chapters in exitance give or take a hundred or so.
If you really want to argue that 100 people can defend an entire planet from an invasion of a thousand ships with millions of soldiers, I imagine you would need quite a lot of time indeed. Source? http://wh40k.lexicanum.com/wiki/List_of_Space_Marine_Chapters http://en.wikipedia.org/wiki/Space_Marines_(Warhammer_40,000) The true fighting power of the imperium is in its navy, its titan legions, and the imperial guard. The space marines are like the navy seals of the imperium. They do special, freaky stuff that ordinary soldiers can't be trusted with or aren't qualified to do. But they aren't by any means the main soldiers of the imperium, and they're a tiny percentage of its fighting power.
Big roughly man-shaped war machine usually around 100 meters tall, built and operated by the adeptus machanicus.
Significatnly large than that, those are the smaller versions, titans can be as big as you want. The fact is, one titan is an epicly rare thing. What makes you think there are legions of them to be used anytime it is felt necessary?
I believe it's stated somewhere that each forge world has its own titan legion, but since they've never said how many forge worlds there are, I agree that we don't really have any idea how many titans there are. But I agree that they're probably insignificant in total fighting power compared to the IG.
Don't forget the Replicators can develop to human form replicators. They're invulnerable to bullets (bolter rounds.etc), and energy weapons. They can also probe the minds of humans and other aliens for information. Replicators also join together to achieve their aims, such as joining to form a replicator titan to fight Imperial titans. That would be a cool sight. (Lol, my first post)
Based on what I have seen I have few question of my own: 1. How the hell are Replicators going to fight against daemons of Chaos? And forget that Chaos cannot influence material universe, Chaos demon can open warp gate using only one individual from any race except Tau. Daemons are mostly melee units, with unnatural powers and they cannot die so easily. 2. Against the Necrons they are helpless. Because they to are machines, Necron lord posses them and use them against their own or against other races of the galaxy. 3. Now against Orks or Tyranids... They are attacking also in numbers, so it would be never ending fight. 4. Eldar would fight them using hit-and-run tactics. But eventually they would use their psyhic powers and Avatar against them so they would be screwed. 5. Tau Empire is very though when it comes to technology. But they lack numbers to fight them, and their best weapon against them would be EMP grenades. But until Replicators get to them in range they will suffer casualties. 6. The Imperium of Man....where to start? -They are known to find solution to any problem, using all necessary means they can. If Replicators conquer an Imperial world, exterminatus and the world is gone. -There is around 1000 Space Marine chapters, each one has around 1000 marines (except some chapters). But, they would use only 10 - 15 to fight against them while other would continue to defend Imperium from it's usual enemies. -Imperial Titans can crush them with weapons and feet, and the Titan driver is connected mentally with the AI of the machine. If Titan encounter the assimilation attempt and cannot defend himself, the driver initiate self destruction of Titan. -Imperium has millions of worlds across the galaxy. I have read somewhere that they lose about 100 worlds per year and colonize 1000. So they have no shortage of worlds and forge worlds counts in thousands upon thousands. But only the most important and advanced one has Titans. Now to ask something else: 1. These Replicators are immune to energy based weapons... But they are from parallel universe, so because 40k universe is different to them they CAN be hurt by Lasguns? 2. They are immune to plasma? Do you know how plasma is hot? Next thing you will tell me that they can walk on the surface of the sun and take pictures Please Register or Log in to view the hidden image! (Just for reference, Tau basic infantry use plasma based technology - pulse rifles. And in Soulstorm intro it doesn't do a thing to SoB armor. And Space Marines have more than powerful enough armor) 3. Find me an evidence that Replicators can dissolve adamantium, yes it is metal - but an unique one because it is nearly indestructible. And there is only one thing in the galaxy that can dissolve it. 4. I will thing of something... In the end my final conclusion: Replicators invade 40k galaxy, do some damage. But in the end... warp powers, Necrons, Tyranids, Orks, psyhic powers, endless swarms of super-solders... they will fail. Mostly because of warp.
