The allegiance battletraits, can be the grand alliance ones, instead of the specific?

[Iradekhorne]

If I can be elegible for an especific allegiance  faction, like Stormcast. I can choose the grand alliance battletraits instead?

For example, if all my units have the khorne keyword, can i choose the traits/artifacts of the grand allegiance Chaos, instead of khorne?

I remember read someting about it somewhere, but i cant remember where xD.

[EMMachine]

6 hours ago, Iradekhorne said:

If I can be elegible for an especific allegiance  faction, like Stormcast. I can choose the grand alliance battletraits instead?

For example, if all my units have the khorne keyword, can i choose the traits/artifacts of the grand allegiance Chaos, instead of khorne?

I remember read someting about it somewhere, but i cant remember where xD.

There are two points.

In the core rules, do to the point Allegiance (Page 17 in the PDF). If you choose the Stormcast Faction (so Judicators are Battleline) you are stuck to Stormcast Eternals Allegiance Abilities. You would have to choose the Grand Allegiance Faction to use Grand Alliance Allegiance Abilities.

There is only one exception in the Errata. If a faction doesn't have there own Allegiance Abilities, can use Grand Alliance Allegiance Abilities instead.