Slitherine

Is there an easy way to mod the persistent campaign roster? Let me explain more precisely what I am trying to do. First, I want to be able to use high-end units such as the Shadowsword or the Land Raider earlier in the campaign - and in greater numbers (you only get 1 Shadowsword for the DLC campaign, and you only get 1 Land Raider for the original campaign - and only for the armies of one character). Second, I am trying to mix both Space Marines and Imperial Guard units in my roster the way you can in WH40K: Armageddon.

Now, I tried to see what can be done with the in-game editor in both respects, and using the in-game editor does not seem to work. Specifically, as for adding high-end units, the added units stay only for that particular scenario and are not persistent. (And they do not appear at all for the DLC campaign.) And mixing units seem impossible, as the game crashes immediately before the scenario begins.

I have been trying to work through this problem for days now, and I would be grateful if anyone can offer detailed help.

There is a file called "ArmyList.txt" in the "Core" folder, in which are all the army lists the game presumably uses for the random skirmish battles of the original and DLC campaigns.
I haven't tried it, but you might be able to change the number of landraiders and shadowswords (and anything else for that matter) there.

To use them earlier in the campaigns... For the random skirmish missions, I don't really know how the game decides which units are loaded into the mission and which ones aren't, I guess it has something to do with the points value.

As far as I can tell, the skirmish missions are set up in the "CampaignDisplay2.bsf" script file located in the "\Data\Scripts" subfolder of the campaign folder, if you want to dig through the code.

Mixing units of different factions is impossible AFAIK. You might get away with creating a new faction which contains all Space Wolves and Guard units, maybe.