Grathoki are one of those demons that are everywhere and in all places. Anywhere that humans and demons cohabit the Grathoki build a market. Grathoki are scavengers of things. They buy, steal, acquire, scrounge, recycle, re-purpose,find, finagle, or in other words get anything they think might have some value elsewhere and then take to the person they think might want it.
Since they are all over the place they have a well-developed network of connections that can be utilized (for a price) and it is a generally accepted wisdom that:
1) If a Grathoki has something in its possession it is for sale.
2) If a Grathoki gives you something for free, it isn't.
Grathoki are bright blue with oily skin and bulging veins. They have shark-like teeth in multiple rows that stick out from their mouth giving them a leering appearance at all times. It doesn't seem to affect their speech, however. They usually dress in normal clothing though hoods, veils, scarves, and high-colors (whichever is fashionable for where they are) are common as they do business with humans and don't want to alarm them.
Grathocki have a low-level telepathy that allows them to understand all forms of communication, and they learn languages quickly. It is generally accepted that a Grathoki will likely speak any local language passably, and will certainly be able to curse in any language fluently.
The low-level telepathy means they are shrewd bargainers as well. While they can't read your mind per-se, they can certainly get a feel for whether you are willing to go up ro down a few dollars more or whether they are being swindled at all.
It really is no joke that ANYTHING a Grathoki thinks belongs to him is for sale. By the same token, a Grathoki who acquires something in what he thinks is a fair trade will assume he owns it. All of it. This includes intangibles like "souls", "virtue", "first-born children"."Arms and legs". Never joke about price with a Grathoki because it is a guarantee that if you say something costs an "arm and a leg" he will be back with both limbs to trade for it.
A Grathoki's name is very dear to him and he won't part with it (as it likely cost him a fair amount of cash) lightly. The number of syllables in a Grathoki name are significant. The more syllables, the more important they are in Grathocki society. Consequently the more syllables in a human name of humans that they deal with, most Grathocki assume that means they are more important. Although they feel that humans are foolish for sharing all the syllables of their name with everyone. A typical mid-level Grathocki name might be GraThaOkJahOpTornKlegNoRiHan (10 syllables) of which he might share the first 4 on a regular basis (Grathaokjah) with casual acquaintances; 6 with business partners (Grathaokjah Optorn), and 8 or 9 with his close family (Grathaokjah Optorn Klegnori). He never shares his final syllable with anyone except the person he bought it from (but they might not know the intervening ones either).
Many scholars believe that the tale of "Rumplestiltskin" is based on a powerful Grathoki (he had 4 secret syllables!).