It's alway tempting to re-use a good setting, and Michael Scott Rohan's popular "Winter of the World" trilogy was nicely located within an interesting variant of Fantasyland in its deep-past guise. This Earth is in the throes of historical ice ages, with the enemy Ice personified as a pantheon of pre-human and anti-life entities who are urging the glaciers on. Louhi, the Finnish Kalevala's queen of storms and cold, logically enough appears as a major Ice power; a mysterious wanderer called Raven (that is, Odin) is on the side of life but reserves the usual godly rights to move in a mysterious way and help only those who help themselves.
In the initial trilogy, mastersmith hero Elof emerges as an avatar of the Kalevala's Ilmarinen, not to mention Wayland Smith, Vulcan and others – at one stage, both his legs are duly crippled. There are conscious Wagnerian echoes, especially in his reforging of a particular sword. While still an apprentice on trial as a potential journeyman, he crafts the "original" Tarnhelm which resonates through later myth. Rohan develops the traditional magic of smiths and smithies into a variety of technofantasy treats as Elof bashes away at his forge and carries on to invent, inter alia, energy accumulators, pressor beams, electroplating, distillation, napalm, powered personal flight and – for the final strike at a central redoubt of the Ice – a close approximation to a tactical nuke.
The Castle of the Winds takes place a millennium or so before Elof's story, with the Ice beginning to stir again after being pushed back by still earlier smiths who have since receded into legend. Our hero Kunrad, yet another mastersmith, is either not quite in Elof's class (being merely human) or is limited in his scope by the fact that Rohan deployed his best coups of magical smithcraft in the original trilogy. Kunrad turns out many good and deadly swords, but is allowed only two masterpieces: a magnificent but obscurely flawed suit of armour whose theft makes it the McGuffin after which he unwisely chases, and the invention of a natural-draught blast furnace which serendipitiously allows advancing Ice forces to be given a taste of not boiling oil but molten steel.
Equally handily, it is in a climactic ordeal by combat that the armour reveals its hidden flaw. Happily this is not one of those medieval technobabble affairs that seem to betray over-research in SCA combat ("See you not how the pauldron jesses catch in the dexter rerebrace and jam his gorget swivel as he essays the fewmet-stroke?") but plausibly uses the established magical affinity between a smith and his creations to imbue the armour with a certain less-than-warlike quality of its maker.
Kunrad's story is told with professional skill and muscular descriptive power; the pages turn pleasurably; but somehow it doesn't have that ring of mythic grandeur which several times sounded in "The Winter of the World". This is at least partly intentional, with the tale being cast as an almost romping adventure rather than an epic – as signalled by joshing or ribald exchanges between Kunrad and his apprentices (one unfailingly randy, one mighty-thewed), and by the almost sarcastic way in which a quest to avenge the bad guy's depredations leads Kunrad to seek aid from a high-ranking noble, referred to only by his title, who when finally encountered proves to be the bad guy. Good marks to Rohan, by the way, for making this Ice-allied but very human villain reasonable, plausible and intermittently likeable.
That splendid lady Diana Wynne Jones has poisoned the well a trifle here. Any reader of her Tough Guide to Fantasyland will experience a thrill of recognition at – for example – Kunrad's early ambush by a dark minion of the Ice, obligatory capture by corsairs, enslavement as a useful human resource (which also happened to Elof), partial befriending of nonhumans, lengthy escape through poisoned marshes and again from an impregnable prison cell, etc.
Of course all this material has long bubbled together in Fantasyland's "cauldron of story", before Jones's satirical handbook of genre tropes. Nevertheless the elements of merely routine fantasy in Castle of the Winds do tend to dilute the parts where Rohan stretches himself with nifty descriptions, frissons of smithcraft, a grisly "Ice Hag" exerting Louhi-like powers, and other nice set-piece scenes. There is also a slightly uneasy tension between doom-laden "Northern Thing" elements – Raven, the Ice, the fey hopelessness of Kunrad's initial quest – and more genially swashbuckling episodes. At one point the latter almost turn into farce when our hero, having escaped the inescapable dungeons, swum to freedom without being able to swim, and swarmed up the eponymous stronghold's wall ("taller than a house of many storeys"), accidentally selects the window of, and thus finds himself in the bedroom of, the very woman whom he rather fancies but whose marriage to the villain has long been arranged.
A pleasant read, considerably overshadowed by its parent trilogy. Comparisons, as Dr Johnson said, are invidious.