Kostchtchie did not know much about Kardum, even though their two planes had once been fairly close. The Abyssal planes were arranged in a spiral, but the Abyss's chaos meant that even two neighboring planes could be separated by an enormous distance. The Sixth Pyre and Frostfell, however, had been very close. In fact, the two planes had practically been adjacent before. Now, because of planar movement, they were actually much farther apart.
In the past, traveling from Frostfell to the Sixth Pyre only required crossing the planar barrier. And the barriers between Abyssal planes were more fragile than a virgin's maidenhead—basically punctured at a poke—so entering had been extremely easy.
Now, however, things were more troublesome. He had to travel through the Styx, and traversing the void was dangerous even for demons.
This caused Kostchtchie no small amount of trouble.
Because he had no money.
In the Abyss, souls were the currency. Precious metals like gold and silver were worthless here. The Abyss contained countless planes, and nearly every one had abundant mineral resources. Open-pit gold mines were actually very common in the Abyss, and demons had little concept of such things.
After all, aside from serving as currency, gold had little additional value. It was too soft; even humans could bite into it. Silver was even worse. Both demons and devils were extremely repulsed by silver, because it made them uncomfortable, as though being pricked by needles. Prolonged contact could even cause their skin to rot, much like humans exposed to radiation.
In the Lower Planes, silver was called "poison sting."
Souls, on the other hand, were different. Souls were absolutely hard currency in the Lower Planes; this was a universal law there. Inferior souls could serve as food for demons, devils, and fiends—the source of their power.