Slitherine

In the dialog box where you can set a unit's traits to "auxiliary" there are also two other check boxes just below the one that says "auxiliary". One is "Special" and the other is "Unique". What exactly are these traits and how do they work? What are they used for? There is the ability to check all three boxes at the same time so I assume they can be used in unison?

Hover your mouse over the question mark.

I believe unique means you can see it on the large screen map when you zoom out.

Special means if it stays alive, it will be available the next scenario, if it is in a campaign.

Auxiliary means it is not a core unit and will not be transferred to the next campaign map.

Special unit:
When you assign a unit to be special, it merely means that you place special emphasis on the unit, like for example a unit that must survive or must be destroyed. A special unit has its strength plate highlighted.

Unique unit:
When you assign a unit to be unique, it must have a name. When the unique unit survives mission A, it will be available in mission B. In every mission the unique unit must be preplaced with the same identical name. This means if this unit is destroyed in mission A, it will not appear in mission B.

Thanks, very informative thread.