Mark of Tzeentch and the Skyshield

[The Man They Call Jayne]

Ok, simple issue here.

I take a squad of 3 Obliterators with the Mark of Tzeentch, this gives then a very handy 4++.

If I then park those Oblits on a Skyshield with its defenses up, which ALSO awards a 4++ save to the models using it, do I now have a 3++ save?

The issue only really arises because the Mark is on the Oblits, not the Skyshield. But the Skyshield gives the Unit a 4++ save and Tzeench boosts any invun save they get by one.

How do we think this works?

[BigToof]

This sounds reasonable...
I mean Skyshield is worded this way, although you won't get any protection from barrages per se, but I think you're otherwise good to  go.
I'd run it by your opponent first just before you deploy so there's no confusion later though.

Best,
-BT

[Raving Bonkers]

Just from the top of my head, as no books to check on at hand, but is it not a cover save you get from a skyshield? So if the mark says invulnerable then people could argue it does not apply? As the two saves are different from each other are they not?

[The Man They Call Jayne]

The Skyshield give you an invunerable save if the shields are up. If they are unfurled then I suspect you only get the area terrain cover save.