Can? Can Arwen of Arnor place the progress token on an inmune location? Is it like Thalin-crows -it 'jumps' the traits-, but about locations?

No, I don't think so. Thalin says he places damage "as" a card is revealed, and we know this damage is placed before any 'when revealed' or other keywords take place.

Warden Arnor says 'the first location revealed,' and does not use the word 'as.' So I would place this token after resolving keywords and When Revealed effects.

Incidentally, I do not know if Thalin should place a damage token on an immune enemy. It might be a moot point -- At present, I do not think any enemies exist who are immune to player card effects but get revealed from the encounter deck during staging. All of them get added to the staging area via quest card effects, it seems. But maybe some are 'revealed' ? Anyway, I wonder if immunity would have a special status and defeat the timing on Thalin's ability.

Surge and when revealed effect are not passive like immunity. Thalin should not damage immune enemy if they get revealed.

And Arwen is the daughter of Elrond, Warden is a title.

Ok, thanks for the answers. Omg, true: how i could wrong the title? It is Warden of Arnor...lol