Land of One City: Well, more like Planet of One City.

The Supreme Guardian’s adoptive daughter is thus educated in politics, economy and military affairs to succeed her mother. Not only are all of Belobog’s Supreme Guardians female, the heir is usually selected not by birthright but through adoption among young girls − and only girls. There also appears to be some mix of elements from Russia's neighbouring countries, based on Sampo's name, which is Finnish in origin, and Seele, whose HI3 counterpart is Estonian. Fantasy Counterpart Culture: Belobog generally appears to be a northern European industrial city with a strong Russian/Slavic influence, as it is not only named after a Slavic god, several characters note Bronya, Cocolia, Pela, Svarog and Natasha bear Slavic names or are Expies of Russian nationals from Honkai Impact 3rd.Endless Winter: Thanks to the Eternal Freeze, Jarilo-VI has been blanketed in a centuries-long winter that sharply reduced its civilization to the city of Belobog.Those who live in the Underground are poverty-stricken, and are forced to resort to desperate measures to survive, especially since the corrupt government abruptly cut off access to the Overworld for, in their eyes, no reason.

The last bastion of humanity isn't exactly the definition of utopia either.

Crapsack World: The entire planet is frozen, and besieged by monsters.

This contributes to his decision to take over the mine since the Furnace Core doesn't actually help in any meaningful way, cutting off the supply of Geomarrow shouldn't pose any actual threat to humanity's survival. The science simply doesn't add up, so he concludes some other factor is holding back the cold. According to Svarog, while the Furnace Core does generate heat, the actual amount it gives off isn't even remotely close to what is needed to protect Belobog from the Eternal Freeze. Geomarrow trade between the Underworld and the Overworld is so important for the survival of humanity that it's the only link kept active after Cocolia ordered the Underworld to be sealed off.

Applied Phlebotinum: Geomarrow is an orange-colored ore largely found underneath Belobog, mined for their heat-inducing properties, thus making it a critical resource for keeping the Furnace Core burning and preventing the Eternal Freeze from freezing the city entirely.

Honkai: star rail belobog