I came across a situation I'm not sure about regarding Lords of War and the Allies matrix. Can't you only take a Lord of War from the same army as your Primary Detachment, if you want to be 'Battle-Forged'?
And since the Allied detachment can not take a Lord of War, if you did that would also make you Unbound.
Example: Adepta Sororitas want to take a Stormlord as a Lord of War.
The Rulebook p119 under 'Battlefield Role' for Lords of War refers you to the Escalation expansion.
Escalation on the first page for Imperial Guard (sorry I only have the ebook version) states that Datasheets in this section may only be taken if your Primary Detachment is Imperial Guard.
So if I want to take a Stormlord, does that then make my Adepta Sororitas army 'unbound'?
Its worth noting that Imperial Knights are not Lords of War and instead add an Imperial Knight Detachment to your Primary detachment (also listed under 'Other' on p119 in the rulebook).