I see this mentioned but have no idea what it is.

Thanks.

A few things to add to this. First, it's possible to go back more than one turn, by doing multiple reversions in a row. That'll hurt your score significantly, of course, and isn't an idea I've ever used.

Secondly, it seems that the same random seed is used when you reverse. That means that (with the possible exception of if you do something requiring the random number generator before clicking 'end turn'), you'll get the same random events. That will, however, allow you to prepare by, say, moving a hero into the province that you know will be attacked by harpies to defend it. You can also choose different options if you got a terrible result.

You cannot go back more than one turn... at least for random maps! I am not sure about the campaign though...

Well, as I say, I never tried. I just noticed it wasn't greyed out, or anything, and assumed it was possible.

With the campaign, incidentally, I believe it also costs energy each time you do it.

Well, I never got round to completing or progressing much in the campaign! It was too frustrating not to have all buildings unlocked; especially when I used to end up with lots of basilisk and slug eggs with no way to recruit them...

Also given the fact that you wouldn't end up doing all the same things that led you undo the last turn... you probably won't see the same random events again. Realised this when I tried to reverse a turn right now - apparently solo warrior without + resistance items doesn't fare too well against shamans!

In a campaign game, you can also do a "back to ether" reversion. Basically, it sends you back to the sherd selection screen BEFORE you started the current shard. It will slightly cripple your energy income (I used it once, and I have an energy loss of 2 each strategic turn. Not crippling, but it motivates me not to use the option too often)
I think this option should be real handy if you're loosing a campaign critical map (a map where you find a Key, or an invasion of your homeworld)

Thanks for pointing that out! That would be helpful IF I ever manage to start another campaign... It's definitely a better option than losing a shard (especially invasions)!

Frankly, the loss of astral income is negligible... as I believe that most shards you conquer give that much income (if not more) when you win them so one reversion on occasion shouldn't be too painful. Obviously, it's a no-brainer when you are about to lose your home-shard.

Thanks for the information! I never made it to that conversation...