The Maker of Universes is a work of metafiction about SFF. The title “The Maker of Universes” refers not just to the Vaernirn “Lords” who create and maintain personalized pocket worlds, or even specifically to the Lord of the realm in which the novel takes place, but to writers who are themselves Makers of Universes.
Consider that the tier-world is made up of various earth myths and pseudomyths that have been molded to the Lord’s whims. Also consider that we are told the Vaernirn cannot truly create on their own, but rather draw on what is available from their more glorious past. If one approaches with a religious world-view, one can take away that Lords/writers are seeking to create with what true tools of creation have been left behind by the true creator; a more secular approach suggests merely that writers do not create beyond that from which they can pull (experience, knowledge, history, example, etc.), hence why the tier-world so strongly reflects earth’s mythos.
Kickaha (or “Kickass-a”, as I like to think of him) is a stand-in for and tribute to all Pulp heroes. Though he’s been in the tier-world for a few decades, he’s an American mid-westerner who left earth in the early 40s; on earth, he would’ve been the age and audience for the pulps. There is more than one off-hand reference to Burroughs made throughout the story, and on the Atlantis tier where Kickaha leads an army of apes, though it’s not explicitly stated, Kickaha is (most likely) known as Tarzan. Kickaha, the pulp hero, is the one man who is able to transition between the tiers of myths with ease (much moreso than the protagonist, for whom it is always a long and agonizing journey), and is a capable hero in all of them. This is because the pulp hero is of myth and mythical, but at the same time transcendent of old myths; the modern pulp hero is as at home in ancient Greece as in medieval Germany as in Atlantis as in an alien’s laser fortress.
Here is where the theory gets a bit dicey and speculative. Extrapolating the writer/creator symbolism, each world created by a Vaernirn represents a body of works. The Vaernirn are lonely solitary creatures, however sometimes a Vaernirn will travel to another Lord’s world, try to displace him and become the new lord (as what has occurred in the plot of The Maker of Universes). The new Lord may twist, distort and bring chaos to the world he has taken. While Farmer makes ample use of homage, he does not tread, even lightly, on the names of other writers; that Kickaha is not EXPLICITLY named as Tarzan is important to this. What we seem to have is a condemnation of other authors moving into a “universe” to try to take it over. Given the time in which Maker was written, this would be understood (with a wink and a nod) to be representative of how the works of pulp greats were being taken over and expanded upon by the less great; Derleth, DeCamp and Carter could easily be cast as rogue Vaerirn Lords who had arrived at the worlds of Lovecraft and Howard, proclaimed themselves Lords and began mucking with the true Lord’s universe, however given Farmer’s Burroughs love, the numerous unauthorized Tarzan stories are just as likely a target.
Ultimately, the Maker of Universes is the story of an older author (Wolff is in his 60s) who trying to reclaim and regrasp his work and creativity; he does this by taking a long journey through it, seeking his muse and uncovering the many facets of his protagonist by adventuring with him. The journey makes him stronger, a better Lord(writer), and revitalizes him. This is why, despite his hypercompetance, Kickaha is insistent that Wolff is the only one who can finish the job and defeat the usurper Lord. Only Wolff knows his world and its inhabitants well enough (though he must fight to remember the details he has forgotten) to arrive at the Laboratories, the factories of creation, from which his world is made and populated and take back the reins.