It probably also depends on the books, or more specifically the writer's idea. I for one cannot imagine any Guard regiment being shipped back home as it sounds .. awfully "humane" for this setting, considering that some interpretations of the setting would make it sound like a waste of resources to provide a transport ship just to ferry a couple hundred or couple thousand (depending on how many survivors there are) no-names across the galaxy.just to be nice, especially if these veterans can further serve the Emperor by becoming settlers.

In the Guard codex at least, it sounded like colonisation being a fixture in a Guard regiment's lifetime .. a question of "when" rather than "if". Of course, the "when" may also be suspended indefinitely depending on the current military situation, so it may well be never if the regiment gets destroyed first before someone remembers they ought to be retired. That's Imperial bureaucracy for ya.

The one exception I remember from those books are the Cadians, who get rotated between the Interior Guard (planetary defence) and the Shock Troops (expeditionary forces). In this case, the Guardsmen's potential return is "justified" as a means of stocking up the PDF with experienced and battle-hardened veterans, just like assignments between both types of forces are based on randomness rather than aptitude to ensure equal ability in both, given the critical importance of holding the so-called Gateway World.

They're fighting for a young, dynamic, expanding empire open to confederation with alien species and preferring peace and trade to outright warfare

Well, tau society is built upon a rigid caste system, feature a rather rigid totalitarian ideology based on absolute obedience to the Ethereals (well, if an Ethereal commands another tau to commit suicide - he'll do it without hesitation). So it's not that simple and clear.

So long as the players don't want to run the Tau Empire, they should be fine.

They come from a settlement run by humans (why wouldn't humans run their own settlements?) with Tau advisors and liaisons - who might not live with the humans, but might visit from time-to-time to check up on things (Water caste to buy and sell things, Earth caste to advise on city planning, fortifications, and building construction, Fire caste (maybe with some Kroot) to lead the militia in drill and recruit volunteers for the auxiliaries - all of whom report back to the Ethereals, who may come to visit in person every now and again, perhaps once a "year" or every two years or so, to discuss matters of state with the settlement's leaders). Yes, the settlement would be taking marching orders from the Ethereals, but that's no different than taking marching orders from a planetary governor or Inquisitor. Except that the Ethereal is generally almost never going to not care about the people that matter to the PCs.

I feel like I should share my experience in OW. I was playing, as a priest, and part of a squad in a regiment that was not really particularly devoted. They were faithful to the Emperor and Imperium of course, but they weren't the kind of screaming zealots you might see in some regiments. This caused some tensions, because while I wasn't playing my priest as the burn-happy madman type, she was still quite devoted and didn't quite mesh with some of the more... irreverent members of the team. The tech-priest, especially.

Generally, the feel of the campaign was something less "you will all die and nothing will ever change" and more "you might win the day here, and be happy you can do that much". There was a lot of emphasis on the fact that our actions had little impact beyond the planet we were fighting on, and the grimdark was toned down, at least on the level we were. It was still pretty horrific, and the campaign involved a lot of doubt if we were actually fighting on the right side (it's a long story, but in short the other side had something that had people convinced it was a Living Saint, and both sides were genuinely convinced they were fighting for the Emperor), but in general?

It was kind of toned down with the grimdark, and it felt like we could still win the day. There was a lot of deaths, both NPC and some PC's, and my priest ended up playing a pretty important role in keeping morale among the Guardsmen up at some of the more trying times. In the end, it was never finished, though.

I like maximum Grimdark for the most part, as long as I have a character that can at least survive a few sessions so I don't feel like filling in the character sheet was a waste of my time.

I like maximum Grimdark for the most part, as long as I have a character that can at least survive a few sessions so I don't feel like filling in the character sheet was a waste of my time.

True. Otherwise you might aswell play paranoia.

I've just made a new character!