So, here's my headcanon about “East Alternia/Beforus” and what happened to it. As I am white, take literally anything I say about culture with a lot of salt, especially where it regards similarities and differences between East Alternian culture and actual real life East and South East Asian cultures. I’m going to be using East Alternia to refer to this cultural sphere on both Alternia and Beforus, unless I feel there is some important aspect of Beforus culture that I need to talk about.
Also this is taking some things from Homestuck, Paradox Space and Hiveswap canon that I found interesting or felt hinted at other things, but I’m not strictly sticking to canon because the narrative belongs to the fandom now and I’ll do as I like with the interesting bits. Mild content warning for fictional cultural genocide and discussion of alien reproduction. Both will be discussed but only in the amount of detail necessary.
So, East Alternia was and maybe still is (in the alpha timeline and at least at the time of Hiveswap in beta-verse) a cultural sphere on Alternia distinct from Alternia in general, or at least we can assume a “Western” Alternia. And culturally there are a lot of parallels (often based on stereotypes) drawn between East Alternia and East Asia on Earth.
Specifically, though, the strongest connections are between East Alternia and Japan.
We know that trolls on Alternia especially are imperialistic and I think with all the meddling that happened with their culture, this wouldn’t have been just HIC and Western Alternia, but other cultures that came up before HIC became Empress.
I think that East Alternia had at one point at the very least its own Mother Grub and its own Condy equivalent. And if anything there were probably a multitude of cultures in the area that were later subsumed into the empire of one Tyrian.
These other cultures may have had their own Tyrians (South East Asian, Chinese or Korean equivalents especially) or may have been completely landwelling and ruled by purplebloods. (Maybe an India equivalent was where some of the tenants of the purpleblood “clown cult” came from, similar to Hinduism or Buddhism, while other aspects came from Western, Roman-esque purplebloods).
But I posit this timeline: A multitude of Trollish cultures spring up throughout East Alternia, all with their own Mother Grubs, leaders and even varying ratios between the different castes. Then, many of these cultures either joined together out of mutual protection, or by going to war where the winning cultural group absorbed the other. Eventually a unified East Alternian Empire was left with cultural similarities to Earth Japan, but still having aspects of other cultures. This was all well before HIC became the Western Alternian Empress. East Alternia became its own cultural and ethnic group to the point that even in “modern” Alternia’s time after HIC unified all of Alternia under her rule, there are family lines that are still considered East Alternian.
It’s hinted at in canon that most of these trolls are lowbloods, and that makes a little bit of sense, coming from HIC and the other Western highbloods’ points of views. I think, as horrific as it would be, HIC had most or all of the original East Alternian Mother Grubs killed, and had all the trolls from across Alternia submit slurry to the Western Alternian Mother Grub(s) (this is also probably about when she instituted collection drones). Any Eastern Alternian Tyrians would have been culled, and many Eastern violetbloods as well, lessening the chance that an Eastern Alternian Tyrian line would show up again. The higher blooded a troll was, the more scrutiny they would be under for obedience, and disobedient trolls of all castes and cultural backgrounds were culled without submitting slurry.
So, the largest number of Eastern family lines that survived were rustbloods and a good number of midbloods. Maybe even cerulean/bluebloods made it through as well. I’d expect only a handful of purple and violet lines combined still exist that came from East Alternia if any, and if Tyrians weren’t rare already, a Tyrian that even came from partial East Alternian stock certainly would be.
I don’t think this was just done with East Alternia either, just that it was one of the more recent additions to the empire before Condy had control of pretty much everything. Most trolls that are East Alternian don’t know much about their culture except what can still be found in older manga/manwa and animation, and they just kind of extrapolate from there. Finding anything about a minority culture within East Alternia as opposed to just Troll!Japan is next to impossible, but there are some things.Alternia as a whole became more homogeneous after HIC gained full control, but at the same time, because of the way that trolls reproduce, entirely new bloodlines of trolls came about at this point in history. While there are still traits that are common or more common in certain ethnic groups among trolls, because they basically combine all their genetics together, entirely new combinations of traits came about. Many Western Alternian trolls have some traits from other ethno-cultural spheres, and vice versus with trolls from bloodlines that are ostensibly from minority ethnic groups, like East Alternians or Gamblinauts - who were implied to be their own ethnic group as well, though I don't remember where this was mentioned.
I did mention that had some specific thoughts about Beforus and here it is:
Because instead of HIC, Feferi was running Beforus, the take over wasn't as violent. Likely, East Beforus was allowed to "keep" at least some Mother Grubs, but I imagine that over time, reproduction was centralized nonetheless. East Beforans had more connection to their traditional cultures than East Alternians, including Damara still speaking with a "strong accent"/her traditional language, which is similar to Japanese in the same way Western Beforan/Alternian is similar to English.