Written shortly before and completed during The Burning Crusade, The Sunwell Trilogy sets up the events preceeding the Blood Elves' joining the horde and reclamation of Quel'Thalas, along with setting up certain characters who appear in the associated zones (notably Dar'khan Drathir) and the eventual Sunwell raid.
Surprisingly, it holds up well despite all the constant retcons surrounding WC3 and later media; only within the intro of the first manga most of the glaring instances of retconning encountered, yet it's an easily skippable part if you've played WC3 and/or TBC-era WoW. Otherwise, the actual plot is fairly straightforward with little in the way of twists or turns - something fishy is going down, a rag-tag team forms to counter it, and eventually triumphs over their much more powerful foe. Otherwise, the story is the largest letdown in the trilogy; it mostly just serves to give a bit of background to Kalec and krew. Oh, and don't forget awkward phrases/writing
Now this is where the manga shines; Jae-hwan Kim does his best to give Warcraft the grittiness it has, but never shows outside of descriptions. Each page is quite detailed in both background and foreground, with characters being decently so.
Given how this is the first time players are introduced to Kalecgos outside of Quel'danas and the Sunwell raid (and given he's the MC of the manga), it does a very good job of setting up who he is and what he believes in. There's fairly decent and believable progression with him and Anveena, even if it gets completely overlooked within the game aside from some key lines in the Kil'Jaeden fight (Guess Blizz didn't learn that separate media tie-ins aren't the best way to set up raids). Aside from those two, the manga follows a similar route with Tyri and Jorad's relationship before they get their own manga and in-game cameos. Targ Highmountain is first encountered here, before his later story in Warcraft: Legends
The other characters otherwise range from "eh" to "forgettable". Dar'Khan at least has nice artwork though
For what it is, the manga isn't too bad, even if the story is thin and it's mostly the artwork and characters which carry the day. Worth checking out, but maybe not buying unless you're really into Warcraft/Blizzard