At the time my book series starts, the western half of the galaxy, regarded as a rural backwater with only one inhabited star system, is undergoing a complete transformation right under the nose of the Ishga Empire, the main power in the galaxy at the time. Here's some further details:
-The Ishga Empire, centered on the planet Ishga (an ecumenopolis in the northeast of the galaxy home to half the galaxy's population) was the first planet to industrialize and it uses its advanced technology and massive population to push around weaker, less advanced planets by colonizing them outright, extracting tribute and resources from them, or forcing them into "unequal treaties" (similar to Victorian Britain). However, its inbred monarchs are starting to become overconfident and complacent.
-The Ishgas pay basically no attention to the western half of the galaxy, as there is only one inhabited planet there (Navayu) and that planet has always been inhabited by "primitive" tribes that have never posed a threat to the rest of the galaxy.
-The vast majority of the galaxy's star systems and planets are uninhabited due to poor atmospheric conditions or simply being off the beaten path. All of the inhabited planets except Navayu are in the eastern half of the galaxy. Only the planets of Aztlan, Atlantea, Planet Squid, Aurea, Rinascita, Olympia, Ishga, Awal, Ryu, Navayu, and Vigam are inhabited, and at the moment all of them except Ishga are weak, technologically backwards, and often disunited entities that are acted upon by the Ishgas more than they are able act themselves.
-The Ishgas closely guard their technological secrets to prevent any other powers from usurping them. While the rest of the galaxy is capable of FTL travel in modified boats via complicated magic I have no time to get into right now, the Ishgas have figured out how to do so technologically rather than magically and better than everyone else. However, FTL travel is the only piece of Ishga technology the rest of the galaxy has a way to copy using magic, and everyone else is fighting with swords and spears (maybe derpy arquebuses if they're really lucky). As a result, the non-Ishga powers are good at international trade but not much else.
Navayu, at the westernmost edge of the galaxy, is so far off the beaten path and removed from everything else that even the lesser powers know very little about it and have little respect for its inhabitants. It has been historically been ruled by a smattering of warring tribes, but a man named Tate (a mutant whose mutation gives him extroardinary magical powers) has recently managed to unify the planet and wants to transform it and the western half of the galaxy into a cudgel to defeat the Ishgas with. In order to do this, he will need to:
-Steal and reverse-engineer enough Ishga technologies and copy enough of their policies to industrialize the planet and catch them up to the Ishgas technologically and societally
-Colonize the galaxy's uninhabited planets and fund his operation using a pyramid scheme called UNISYN I'll try to explain succinctly: Tate takes advantage of the portion of uninhabitable worlds with usable atmospheres but are off the beaten path to encourage people on Ishga and elsewhere to buy land on and move there. People who buy land here are encouraged to get their friends to buy land here, etc., etc., until these worlds are settled. Tate will also need to find a way to get these people to be loyal to him without directly annexing these UNISYN colonies.
-Multiply Navayu's population by at least 10 using a "child quota" policy (basically the opposite of China's one child policy).
-And most importantly, Tate must accomplish these objectives with the Ishga Government taking notice of exactly none of it.
How would Navayu catch up to the Ishgas in this scenario, or how would any minor power catch up to a superpower without said superpower noticing?