Ah, no, that's unfair of me. I don't want to do The Complete Necromancer's Handbook all over again. The Book of Nine Swords (Richard Bake, Mathhew Sernett, Frank Brunner) is a book published for the Dungeons and Dragons roleplaying game, and therefor it is part of what D&D is. I don't need to go making snarky comments about how surprised I am that it's a vision of the game that includes heroic warriors doing awesome feats of valor and skill beyond the capabilities of normal human beings, nor do I need to smugly say that this feels like a departure from the tone set by Dungeons and Dragons thus far.
The Introduction does that for me.
If I were inclined to waste space, I would just quote the entirety of the "Behind the Curtain: Blending Genres" sidebar for you now. It's an absolutely wild ride through the hang-ups and prejudices of the early 2000s D&D scene:
Thanks to the influence of Japanese anime, Hong Kong action movies, and popular video games, the notion of a fantasy setting has grown very broad in the last few years. Fantasy gaming isn't just about knights and castles and dragons anymore . . . More than any other, this book represents "culture-blind" D&D: fantasy gaming in a world where silent ninjas and wandering kung-fu masters live side-by-side with noble paladins and fearsome monsters. Tome of Battle isn't your parents' D&D - it's bigger, bolder, and more fantastic than ever before.
Also, it's much better for "traditional" fantasy. Want to play as mechanically-distinct Knights of the Round Table? Book of Nine Swords. Want to play a leader of men, tactically cunning and peerless on the field of battle? Book of Nine Swords. Want to play a determined survivor, who can get the absolute shit beat out of them and still rise to fight against impossible odds? You can see where I'm going with this.
Book of Nine Swords isn't notably East Asian in its aesthetics (except for a couple of outliers like the Jade Phoenix Mages or the Shadow Sun Ninjas) - it just makes warriors impressive. Conceptually, Warblades are just the Fighter class (their niche is that they are warriors who are skilled with weapons), but they are allowed to do cool shit. By 2006, organized HEMA had been around long enough that it shouldn't have really seemed all that shocking to have a "western fantasy" book about legendarily effective martial arts.
And yet Book of Nine Swords does manage to feel thrilling, even today. It presaged fourth edition, and in many ways failed to reach the heights of 4e at its best, but also, because it was explicitly an experimental book, it was allowed to be bold in its flavor. It knew the hidebound elements in the D&D fandom would never accept it, so it didn't have to try and be "generic." You could have the Ruby Knight Vindicators, dark paladins of the Witch Goddess Wee Jas, who hunt down and slay those that would threaten the faithful, and it's a weird, highly specific thing. But also, it's undeniably European, undeniably fantasy, and undeniably something that D&D has always implied that you could do.
In case you couldn't tell, I love this book. It's got the self-conscious swagger of someone who has just knowingly and deliberately pulled the stick out of their ass. Maybe it can be a little awkward at times. The Sun Shadow Ninja class has an unnecessarily defensive bit of DM advice - "the word 'ninja' strikes many DMs as an anachronism, or at least a misplaced cultural element" (come on, just own that shit already). But it's earned the right to flex a little. There's an elf prestige class whose power is basically having Navi from Ocarina of Time. Okay, we can get a Fine-sized flying, incorporeal familiar who "appears as a mote of white energy" and shows us enemy weak points. I see what you're doing, Book of Nine Swords . . . and I'm totally on board.
Maybe it's because this book is as close as D&D ever gets to being Exalted ("Oh really? Can you play a reincarnating warrior-mage with a sacred mission that spans multiple eras of history?" "Yes."), but I wish I saw more stuff like this - non-caster classes designed around a principle other than "numbers get bigger." That's what fantasy is to me - a world of grander scale, where wonder and spectacle can be found in anything. My only real complaint about this book is that there's not enough out-of-combat utility. I love the idea of swording so effectively that you can just start cutting away peoples' souls and shit, but I kind of want to take the other arenas to the same level - silver-tongued diplomats who can confound with carefully-chosen words, epic feats of strength like tearing down a stone wall or diverting a river with a hurled boulder, stealing a well-guarded treasure in broad daylight and then revealing that the real heist happened 20 minutes ago. Magical and fantastic characters that aren't tied to D&D's highly idiosyncratic spellcasting system.
Book of Nine Swords doesn't quite get us there, but it's a start.
Ukss Contribution: This is another one of those books where I'm spoiled for choice. I kind of want to pick the Jade Phoenix mages, but they are literally just D&D's take on the concept of celestial Exalted. I've also got a few standout maneuvers that I really enjoyed, but they aren't so much "distinctive setting ideas" as they are "things you should always have been able to do" like throw an enemy into another enemy or jump on a big creature's back and just go absolutely berserk while it tries to wrestle you to the ground.
So I'm going to go with something that was suggested, but not fully developed. The Eighty Empresses. We don't know much about them, other than the fact that their leader was fond of insufferable riddles ("How does a sword mean?" Really? Blech Forktongue was right to start tearing apart the furniture), but we do get their initiation ceremony - "The masters bring each young lady separately into the Dressing Room of Opala I, whose walls, mirrors, incense lamps, pots of rouge, and songbird cages are draped with 1080 gold, pink, orange and fuchsia silk ribbons . . . After she leaves, one ribbon is removed from the room. . . If she can name the color of the ribbon that was removed, she is accepted."
I can't say with certainty, but I don't think that D&D has done anything so unapologetically feminine, either before or since. Whatever "genre-blending" they did to get to this point was obviously good for them. I want to honor that by putting the Eighty Empresses in Ukss.