I follow numerous stories and quite appreciate a tiny ‘In our last episode. . . .’ summary of a sentence or so to get snapped right in as I start to read a new episode. I noted that you sort of did this at the beginning of Chapter 4 and it was particularly helpful to me in this case as I have ‘offline’ for about a week. I encourage to you to fully adopt and maintain this wonderful courtesy for your readers.

You’ll notice that several writers do so in their own fiction threads.
Let me also say how much I appreciate (as I’m sure mALX and SubRosa do) your reading and commenting on each or our sagas in the ‘Commentasaurus’ thread. It is gratifying to hear your wonderfully welcome observations!
‘The sound of tumblers falling into place and a slightly squeaky hinge proclaimed success. There was a thunderous crash somewhere on a floor above us, proclaiming the keep was no longer undamaged.’ -- I quote this for two reasons. Firstly, I love your use of sound to obliquely, but clearly tell us, what is happening here – wonderfully done! Secondly, the word ‘proclaim’ is rather distinctive – enough so that when used twice in close proximity it detracts from the stellar quality of this passage. Alternatives for one of the ‘proclaim’ uses might be variations of announce, attest or perhaps declare.
We don’t see a lot of axe fighting descriptions in fanfics here and I really liked your description of Valrimor’s use of one that favored finesse and momentum over brute strength.
And we see Val is quite the skilled thief with a lockpick. Woot! Wine, a bow and plenty of arrows! What else could a wood elven rogue need?
’The dragon announced its culpability with a distant roar.’ – - Again, I love your use of sound to enrich your descriptions!
‘I hated spiders. Ralof actually vocalized his shared opinion.’ – - Val and Ralof have plenty of company among the various characters here at Chorrol! How clever to 'milk' them for poison.
“Poison is a drunken archer’s best friend.” – -
This story continues to be simply a delight to read!
Nits:
You are a bit inconsistent regarding punctuating your dialogue. I recommend Googling ‘dialogue punctuation’, which can shine plenty of light on this rather complex art. Here are a few selected examples from Chapter 4 regarding comma vs period use:
“Damn, that dragon doesn’t give up easy.” said Ralof.’ -- The period after ‘easy’ should be a comma.
“I got it all,” I said to the others, “let’s keep moving.” -- This passage is perfect. The speech tag is effectively inserted in the middle of a sentence of dialogue.
“No.” she replied, “I haven’t seen him since the dragon showed up.” –- The period after ‘No’ should be a comma since you are linking the speech tag to that clause (by not capitalizing ‘she’). Use of a comma or period after ‘replied’ depends on your intent. You could keep the comma after ‘replied’ if you intend the entire passage to be one sentence of dialogue. On the other hand, if you intend the last clause to be a new sentence or statement, you would precede it by a period. Confusing, eh?

It was our own SubRosa that really helped me get a handle on dialogue punctuation and, as I implied above, I found that doing some internet research on the subject proved very helpful.
’Looking that the other dead Imperials, I found two more quivers.’ – - (From Chapter 5) I suspect you wanted ‘at’ instead of ‘that’.