This is a piece about Warhammer and Nietzsche, pertaining particularly to his concept of the Ubermensch. I quite enjoy Nietzsche (not the same as always agreeing with him). And while I actually do think there is a case for quite a few of his takes (Genealogy of Morals and Anti-Education are important works with a lot of merit as anti-establishment dissent), I'm uncertain about his concept of the "ubermensch", the Nietzschean superman. But it's the latter that is the topic of this post, and I think it does have some interesting relevance to Warhammer lore.
Obviously, the first thing to come up when broaching this topic are Space Marines. But I would say that the SM are in fact a poor example of the ubermensch. Similarly to how Nietzsche's concept was appropriated by the most horrifying regime of the 20th century (Aryan supermen), the similarities are predominantly superficial (and, truly, it is unfortunate for such an interesting if prickly thinker like FN to be tarnished by such association). Nietzsche was not concerned foremost with brawn or aestheticism but with a stubborn will toward self-actualising. To borrow an over-used term, it's a mindset, not genetic inheritance. So, while marines literally are literal 'super-men', the eugenics and lack of self-determination do not fit with the ubermensch ideal.
To move this onto the Stormcast, who I believe are more fitting embodiments of the idea, I want to touch on the idea of 'slave morality'. Cribbing from Nietzsche here: for the Greeks, the duality was was between good and bad i.e. good was synonymous with nobility and strength, while bad was the plebeian, weak and the low. This was what Christianity successfully reacted against, based on the revolutionary idea that the formerly "bad" values of passivity, weakness and "turning the other cheek" should be re-categorised as 'good', while many of the ways that 'good' nobility expressed its strength upon the low was not only not "good" but a new moral category: evil. Both 40K and AoS exist in a context different from 'modern' morality (i.e. the idea of peaceful, passive good vs invasive, malicious evil found in the Abrahamic religions). In the world of warhammer, deities are literally real, active (and not simply to be interpreted by the priestly class), and essentially deny the creation of any such morality based on the veneration of passive resistance.
AoS's Stormcast eternals may at first seem to be a simplistic version of the traditional "golden goodies", but there's actually some interesting stuff to dissect there. N's concept is essentially an idea of a, a subject who rises above modern "slave" morality to forge their own, self-affirming lifestyle. Of course, the SCE serve their god Sigmar, but the military hierarchy is one which allows for the questioning and debating of individuals. It's not a collective which suppresses dissenting assertions of will, and ironically (though obviously, this is GW's authorial choice), such freedom to 'be' has meant zero defections to chaos among their ranks. Sure, they operate as part of a uniformed collective, but the point of the ubermensch is not necessarily isolated individualism but how the personal glory and strength of an individual elevates all. After all, Sigmar plucks only the greatest warriors from their moment of death and invites them into his service. More than just the "Blonde Beasts" conquering and asserting their power across the realms, SCE protect the vulnerable from Chaos, which you could interpret as a version of what N describes as a healthy creditor-debtor relationship: the stormcast gain satisfaction from saving the powerless through the expression of their own superior power (a more effective form of strength assertion than Khornate slaughter), while cultivating the safety of a mutually beneficial civilisation. Basically, their mission of humanitarian liberation is intertwined with an individualist mission for existential 'meaning'.
On that subject, Nietzsche's rejection of morality initially sounds like it would apply to Chaos best of all. To a certain extent, this is true, as all of the Chaos gods but Nurgle embody a different facet of Nietzschian ideals, whether it be the physical assertion of power, the pursuit of Dionysian desire and pleasure or the cultivation of one's own skill and power. Yet part of what makes chaos is how these positive ideas are warped to the point of self-destruction, this dogmatism becoming its own form of bad consciousness.
Archaon (and Abbadon in 40k) stands as the only true chaos Ubermensch, while Stormcast society finds a way for a multitude dedicated to the ideal to flourish. Despite their creepily expressionless facemasks, the Stormcast seem to be represented in the stories as partaking in drink, telling jokes and generally keeping a semblance of Dionysian virtue alive. They fight for a cause which they choose to follow, and are unimpeded in the ability to desire. And, of course, there's the fact that they come from all walks of life, classes and genders. The ranks of the SCE are a true meritocracy, allowing individuals to flourish within the context of the collective.
HOWEVER, there is one massive caveat to the idea of the SE as Ubermensch: the 'eternal' aspect. This, ironically, is reminiscent of Nietzsche's 'eternal recurrence' thought experiment: the idea that, if one was to live out one's life infinitely, repetitiously, the subject would ave to struggle to overcome a 'ressentiment' about their existence. And this is LITERALLY WHAT HAPPENS to a Stormcast: with each death and rebirth, an increasing 'copy of a copy of a...' chain, they lose a portion of 'humanity'. This loss is represented the lack of emotion and mindless heed of orders; essentially the loss of personal desire and the internalisation of ressentiment. They express strength no longer as individuals but as passive conduits of Sigmar's will, and so fail to retain their ubermensch status. One could say that their eventual fate is to become... Slaves to the Sigmar's command; slaves to Sigmar's morality?
So yeah, my thesis is that the Stormcast eternal is the ubermensch but with a shelf-life. They are initially a shining exemplar of the ideal but degrade into its parody.
All of this is also a charitable reading of Nietzsche's ideas, but I'm inclined to say that's usually the best way to approach him. Nietzsche is often placed in the same category are Freud in terms of massively influential intellectuals whose ideas don't stand up to scrutiny, but I'll go to bat for Nietzsche. A bit. Not Freud, though, especially for influencing his nephew Edward Bernays .