Hi.

Bringing a card out of Shadows is considered a player action? By this entry in the rules I would assume it is: "Each card that comes out of Shadows is treated as a separate action, [...]".

So, Alchemist's Guild Hall can trigger on itself?

Alchemist's Guild Hall is a card with the Shadow crest and: "Response: after a card comes out of Shadows, kneel Alchemist's Guild Hall to choose and kneel a character or location that does not have the Shadow crest".

When I bring Alchemist's Guild Hall out of Shadows, it's fully in play at step 3 of "player action window", so, it can immediately trigger its response at step 5? Does not have to waint until a second card exits from the Shadows, right?

Thank you!

Yes, "After a card comes out of Shadows..." type responses on Shadow cards can be triggered in response to these cards themselves coming out of Shadows.

*Sigh* A bit of a *********** of a sentence. In short: Yes, you can.