I would assume it would be Cato Sicarius, and not Captain Agemman of the 1st Company. That's what most sources hint at anyways, even though tradition dictates that the Captain of the 1st company should be the next in line for Chapter Master should the Chapter Master fall.

So they then replace their beloved chapter master and assault Tau space with a man that just got promoted and little time to adjust to the change. The new master would be fighting in a whole new command with the emotional response of losing calgar and, in general, the SM with him.

which gives me the thought: If the whole company were destroyed in that event on Malbede, then how would the rest of the chapter even guess the Tau's involvement? they would just as soon blame the Necrons (and the Necrons can't/don't care to react to the accusation ) Than the newer, less notorious Tau.

Actually, judging by BL books and the like, the Necrons aren't that well known among the Imperium, even among its military circles--so the Tau, who the UMs know as the more active in the region, would probably be blamed first.

Yes, that is a good point.

But in most of the engagements the SM have had with the Necron were not measly battles, and the Tau again are not very notorious to the SM and they would go to Malbede anyway to investigate and find the Necrons over their fallen brothers and simply put 2 and 2 together. And they would probably initiate Exterminatus and destroy Malbede .

Your post is kinda irrelevant considering that Calgar wasn't killed at Malbede. However, if Calgar was killed by the Tau at some future date, and Sicarius did take command over the Ultramarines he would likely hold nothing back in a war of vengeance against the Tau. As it was, he wanted to continue the Zeist Campaign into sovereign Tau space, and only a direct order from Calgar stayed his hand.

Good point, I was just refering to the "what if" point of view.

However, I wonder if the imperium would at one point come to an alliance with the Tau, seeing as even the Ultramarines value their skill in battle. It would be unlikly for the Imperium as a whole to accept the xeno hand of the Tau since they are not human, but the Tau is the only alien race that does not openly despise the Imperium. And the Astartes somewhat admire the Tau to a degree. It would also benefit both factions aswell since they fight a common foe. The Tyranids are threatening the region and both Tau and Humanity do not want them around more than the Imperial forces nearby want the Tau gone and vice versa. The Tau would love to have the Imperium on their side and would rush at the chance of peace and mutual benefit.

That is more or less what happened when Hive Fleet Gorgon attacked--the Tau and some Cadians were able to join up to fight off the 'Nids.

However, the Imperium being the Imperium, the Cadians decided shortly thereafter that they may as well cut off two heads in one blow, and went for the Tau as soon as Gorgon was defeated. What happened next, we'll likely find out in the next Tau codex. :p

The problem for the imperium if they were to ally permanently with the tau or even just deciding to live and let live is that it would lead to definite Tau dominance, don't forget the speed at which the Tau have developed their sciences and increased in number, while the imperium have been using mostly the same tech since the 31st millennium (a 11,000 year span) and have lost many more people and planets than they have gained since the heresy. Even if tau progress slows significantly they would still gain a huge advantage if left to their own devices.

I guess that what I’m saying is the imperium kind of know they are waning and the Tau are growing so now is likely the only time they will have such an upper hand is now so to just leave the Tau to do their own thing would only speed that transition.

We can say the Tau aren't as bad as many of the other races but they could be a massive threat if left to develop. The orks and dark/normal eldar, necrons and chaos are as slow changing as the imperium and no side is ever likely to completely overwhelm the other. I would argue the nids and Tau are the greatest threats to the imperium, both due to their ability to adapt and grow if left unchecked. Don't forget the Tau are out to destroy the imperium, maybe not kill all mankind but to at least convert all to the greater good and away from the god emperor.

Agreed, but even by themselves the Imperium is imploding under domestic conflict caused by the stagnation of indiversity. An alliance with the Tau benefits the Imperium by the numbness the Tau have with the warp that humanity can utlize at the cadian gate. Also, if the Imperium allowed the Tau to trade in human economy, the Imperium could make a technological comeback. Thus, if the Imperium advances in technology they could better defend themselves against a possible Tau "unfriendly expanse".

However, even if the Tau and Imperium were to ally, I find it hard to believe that the eternal war would shift very much due to the many fronts to handle.

Given that the majority of the Imperium is indoctrinated into viewing contact with aliens, let alone use of their tech, as blasphemy, that's unlikely.

Besides, the Imperium does have some modicum of justification in not fully trusting the Tau in that, in the end, the Tau really do believe in 'our way or highway'--sooner or later, they're going to try and wrestle power away from the Imperium's leaders.

Why would Calgar keep Sicaius from assaulting the Tau? How come he is the only person that likes the Tau? Has he developed a soft-spot for the Tau, or does he value them in some way? I've been told that Calgar would'nt hesitate to obliterate the Tau under these kinds of circumstances, yet he seems to want them alive. What happened to Calgar to stay the hand that can cripple the Tau if not extinct them?

I'm so confused with this ceace-fire/peace/assissting/hating the other!!

What's hilarious is that the 'god emperor' would probably appreciate the Tau and would be more likely to ally.

He never wanted to be revered as a god, for one thing...

If you read the Ultramarines Codex, the Zeist Campaign texts tells you that the Imperial Tarot predicted hard times ahead or something. The coalition of various marine chapters, although impressive to say the least (almost always at chapter strength), would have suffered too many casualties.

The Imperium's position on Xenos is precisely for situations like the Tau and not those of the Tyranids, Orks or Necrons. I'm pretty sure that this is one of the things the Emperor was fairly serious about.

It's easy to be xenophobic when you're encounter with aliens is that they want to eat your face or worse, it's a lot harder when they want to make your life easier and sell you things. However, you are either in control and find that it's easier to hand your manufacturing over to the aliens because they are just dumb beasts who don't know any better and are more efficient that potentially rebellious humans (which encourages the spread of those aliens, increases local dissatisfaction and equips said aliens with technology beyond their current reach) or you find yourself increasingly in debt to an unfriendly power and every step to get away from this becomes harder and harder due it requiring the collapse of your economy, the removal of now-common medical tech and the various other luxuries people have got used to.

With the Tau, by the time a planetary governor realises they are in too deep once the Tau start jacking up the quotas to deal with the 'disruption caused by misplaced Imperial aggression in neighbouring areas" they can't say no without having their citizens or supports staging a coup to stop them taking away their fancy toys.

And on top of this you have the actual problems the Imperium is trying to prevent that the Tau Empire just hasn't come into real contact with. The Tau empire hasn't had to deal with the stuff the Imperium has and might not even make it past their singularity. There's a reason that the Imperium survived so long, to think that the Tau empire is going to be able to do things differently is as arrogant as thinking that you could invent a new tank better than those currently used.

Far as diplomats go, the two will probably deal fairly cordially with each other, knowing that they are both playing a game (and a game that both have played locally as well) but with higher stakes. On a day to day level, the xenophobia of places on the Eastern fringe is going to be ramped up more than usual whenever they can (didn't the cardinal/bishpop of Brimlock call for the Damocles Crusade?).

Marines can of course ignore all of this, and will be in a better position because of it - they lose nothing to co-operating with the Tau and doing so means they are more likely to get prisoners back. Then again I can see the reasoning that says the last thing the Astartes would want is for the Tau to get their hands on functioning Astartes biology.

What if they were to ally for a different reason? Like gain knowledge into the Tau's technological methods and weakpoints in trade that is monitored and kept from the imperial economy. They could do that by allowing the Tau trade to 1 planet saying that from there their goods are transported appropriatly by imperial convoy but instead researched and understood by a pre set team. It would be better than finding battle-worn equipment that is most likely damaged and isn't a proper sample. Plus they can save soldiers if they add a force with advanced and reckonable technology.

Only small subsets of the AdMech and Inquisition would really be interested in appropriating Tau technology, and they certainly wouldn't apply it to any meaningful scale. Remember that most Joe Schmoes in the Imperium, and even many SMs, find even touching alien technology distasteful.

And then you must remember that the Tau aren't going to be dim enough to simply give away any technology that may give the Imperium advantage, much less let them transport it on their own terms.

The Tau have had about 2000 years to come up with their technology, humanity has had 38,000. From the Imperium's point of view, humanity wouldn't have survived if they hadn't come across the best solutions - sure a pulse rifle is a better standard armament for a rifleman than a lasgun, and a drone network AI is likely more complex and useful than uploading a wolf or bear. However, a lasgun is sustainable, durable and 100% with lasguns is better than having 10% with pulse rifles and 90% with nothing. A loyal but basic mind in your titan is better than fighting an AI uprising against titans, or falling for the ultimately self defeating path of the post-human.

If your stated goal is the continued survival of the human race, then having humans being a fairly integral part of that is pretty important. To divert dangerously into Realworld territory for the moment, western civilisation isn't sustainable, not for any particular environmental reason but because we require immigration to maintain our populations. Humanity with eudamonic Tau empire tech, is a civilisation of ghost towns populated by our abandoned AI servants, and if you're lucky a single insane post human in the middle. The Imperium has lasted longer than any other civilisation in the history of mankind, and it does so because it is set up purely to continue to exist. There's a reason it's almost literally built from Human Flesh and Human Blood, and that is because it's supposed to make sure there is always Human flesh and blood for it to use.

Far as the Imperium is concerned, the Tau Empire is very much a short term thinker - only really considering a future a few centuries or a millennia or two in advance. A single human might be interested in what the Tau can offer, but the Imperium as a whole has been there and done that, and isn't really interested.

Tastyfish: the Imperium may have been around that long, but their technology has not advanced for about 11,000 years and the Tau are in most regards a match for the imperium technologically. The imperium knows that they can adapt very fast to problems, and even though the Tau are young, they have grown and evolved faster than humanity. Imagine where the Tau would be when they have ben around for as long as the Imperium . The idea that the Imperium is that ignorant to the bigger picture of the Tau's rate of advance is blasphemous!

but they are... at least those that aren't rocking space marine hax.

Remember, humanity was advancing just as fast back in the day. Then there was that whole 'Dark Age of Technology' nonsense. Now humanity is content with what they have to prevent the same thing from happening again. Maybe the Tau won't have a dark age also, but maybe they will?