I was never attached to the character of Nemiel, but that's not to say I was calling for his head. Rather, I wanted both him and Zahariel to become more fleshed out and interesting.
I agree that the Lion's fluff is out there. Practically every story he's been in thus far has shown him in a radically different light. In Descent of Angels,
he would appear gregarious and well-meaning one scene, only to be ruthless and secretive in another. In Fallen Angels
we get very little insight on his character and have to instead rely on Nemiel's bizarre observations. In "Savage Weapons", we get a taciturn knight-primarch who balances nobility with pragmatism. In The Lion
we see a potentially psychotic killer who may or may not be talking to himself and makes highly questionably decisions. In The Unremembered Empire
the Lion combines his decision-making from The Lion
with his personality from "Savage Weapons" - though Guilliman is able to overcome his barriers and gets his brother to finally express some of his worries.
I expressed my thoughts about "Master of the First" in another forum already:
I can't say I was really a fan of this particular work. It's satisfying in that it provides an update on the doings in Caliban, and provides some light in the actions of Luther and Astelan specifically, but much of it struck me as the product of author's fiat. The conclusion wasn't that great, in my opinion.
The voice acting is quite good, with one glaring exception:
The general plot more or less connects with what we "knew" from Angels of Darkness:
Neat little tidbit of info:
The low point of this audio drama:
"Master of the First" is 35 minutes long. It adds valuable insight to Astelan's mindset. Other than that, though, I wouldn't recommend it unless someone was driven to be a completionist where the lore of the Dark Angels or the Horus Heresy are concerned.