gaining shroud as an aura hits

[Pastorofmuppets]

Let's say I have a Naya Hushblade and then play Shield of the Oversoul.
I'm assuming that since it already declared its target, the aura won't fall off and I'll have a 5/4 flying, indestructible, shroud guy.

[majikal]

Correct.

[luma]

Auras target only while they are on the stack. If you have no other multicolored permanents, the Hushblade will have shroud only when the Shield is already on the battlefield and attached to the Hushblade. Then the shroud doesn't matter since the aura doesn't target anymore. You will have a 5/4 flying, indestructible creature with shroud.

[Nihil Credo]

As a matter of fact, fourteenth-pick Sigil of the Nayan Gods was quite a powerful combo with the Hushblade in Shards limited.