tl;dr
Adult Kiroshi are almost entirely wolf men and women, divided between big hunky muscular adults and then shotajijis and lolibabas who underwent a ritual to de-age themselves. Slaves come in three types:
Breeding slaves (male or female), who are picked for their robustness.
Milk slaves (female or futa, if that's applicable), who are picked for their massive breasts.
Pleasure slaves (male or female), who are usually a part of an Elder's harem due to their unique traits or position before being enslaved.
Hakuboya was a settled land before the endless winter and yukishini gas made it mostly uninhabitable, so you could have any kind of hermit/wanderer living there as well.
Slavery is different between the canal-cities. Some 'slaves' are treated more like Kiroshi with extra duties with only a single partner for life, while in other canal-cities slaves are treated as free use holes with no rights. For reference, Ginko's canal-city of Chonyn Tal is somewhere in the middle; some wolves take slaves as husbands and wives, while most are either in harems or are cared for in the breeding dens where any Kiroshi can use them freely.
More secret still is Modori. When the Kiroshi first settled, many died from the yukishini; a few, however, were changed. Elders rose from trances younger than their grandchildren's progeny. Over years, a drawn out and time consuming ritual with the vapors that returns the supplicant to the cusp of puberty was iterated on. Some side-effects include hematolagnia, b̸̢̧͍͇͖̖͈͎̬̥̗̮̳̌͗͂̕͜͠l̵̡̰̙̖̙̜̾̆͐̃ö̶̪͓̞̘̜̬̼̩̳́̾̒̃͆̄͒̈́͂̂̍͋̓̈́̂̕ͅo̷̧͔͒̉̓́̉̀̎͗̄̌̔̀́͝d̸̡̡̙̺͇̪͔̣̗̓́̊̉͋͊̏̄̎͐̈́͛͑̀͒̕͜͝ ̴̟̲̩͇̤̝͎͍̯̻̝͈̋͊̀̾̈́̅̾̃̍̀̑́̈́̓͝ͅṟ̵̮̞̠̲̳̔̓̾͊͋a̷̯̩̋̌̀̐́̒̽̂͋g̸͈̪̥͓̥͈͉̥̯̪̩̹̱̞͆̄͌̃͑̃́͑͝͝ę̶̭̥̟̥͖̠̺̰͇̻͇̦̄̈́͗̈́̈͆̈́̓́̊̃̽͘͝ͅ, mild anhedonia, infertility due to prepubescence, and dependence on the Modori, less all those years and more come back at once. One in four Kiroshi have undergone this ritual, and the eldest amongst them (around 80 years of age, where even the Modori's effects cannot stave off the end) puff from pipes containing concentrated Modori, subjecting those nearby to limited effects of the yukishini.
The current claimants of the unwanted land of Hakuboya are the Kiroshi, the remnants of many wolf clans exiled from the grasslands. Settling the land some forty years prior, they've been a growing terror to the commoners and lesser nobles amongst neighbors. They bear similarity to humans physically but have the ears, tails, fangs and claws of wolves, while being stronger, having a 'sharper' temperament. Builders and architects of many of Aishiji's fortresses and palaces for a hundred years, a court plot rumored to have been enacted by foxes and tanukis saw their fortunes reversed. Stripped of their titles, riches and lands, they were exiled. Many gave into banditry, or fell into service with other lords. Those that did not traveled as far from the Shogun's court as they could; Hakuboya, the snowy plains. The province's cities were ruins, uninhabitable in the blizzards. The many disparate canals of Ieyasu's Folly became their sanctuary as they hewed and shaped the frozen over waterways into shelters, then towns, and ultimately frozen fortresses buried in the ice. The yukishini, first a curse, was by chance found to hold powers that would see them fit to enact their revenge on the capitol, decades in the making. They maintain some of the court's fashions, vibrant colors, sigils and patterns of now defunct clans now are donned as arm and leg wrappings as they wear split robes, woven sashes, thick scarfs and heavy boots instead of the silk and slippers of the warmer south.