Situation:

Valar is revealed.

Damphair dies and become an agenda.

Now do you get to draw cards off him immediately when the the other characters are saved?

No - for a few reasons:

1. When you reveal Valar, all characters are saved before any of them die. Damphair will not be dead before you save any other characters
2. When Damphair dies and becomes an Agenda, he is moving from an "in-play" state to an "out-of-play" state; that means he remains in-play, though moribund, through the remainder of the action window (including responses to plots being revealed, etc.).
3. While he remains in-play, he is just a character, with no "access" to his agenda text

What this all boils down to is that the action window in which Damphair is killed has to close completely before he actually becomes an agenda - allowing you to draw when a character is saved. You will never be able to draw for a character saved from the same effect that kills Damphair.

Just to clarify: is it merely the fact that he becomes moribund which prevents you from doing this?

If, say, it didn't have the whole thing about being an agenda and merely said "attach to your house card" then he'd attach immediately as he doesn't leave play, and you'd be able to trigger his newly gained text in response to the saves?

Circadia said:

It would depend on the actual wording of the card.

As is, his draw effect can only be used from out-of-play while he is an agenda. Therefore, he needs to physically leave play before you have access to it. If he were worded in such a way that his draw effect is triggered while he is in play, and that he didn't need to leave play before gaining the text, you could use him in response to saves to the same killing effect. But it really would depend on the wording.

So, short version - it isn't the "moribund" thing that makes you wait so much as the fact that his text is only active after he is physically removed from play. You'd need to reword him in such a way that his text is active while in-play in order to get an "immediate pay-off."

ktom said:

What I mean is, if he wasn't attaching as an agenda and just as an attachment, and if he had text that said "while Aeron Damphair is an attachment, he gains Response: blah blah", then he'd gain that text immediately upon attaching to your house card and could be triggered in the same action window that produced the effect that killed him. It's only because he has to leave play (in step 6, after responses) that his text doesn't appear until the action window closes.

Circadia said:

Indeed.