At the same time, all his worlds are always detailed down to the smallest details (this does not mean that other GMs have something bad; I played with Nebk, it's lighter there, but everything is still well-written and clear). And if the player's character is able to fit into the internal rules of the game universe, then even then, no one guarantees that his fate will turn out perfectly. Although the chances of success will certainly be higher than if the character is an isekai character in the world and behaves as randomly as possible.
Fights with the GM's characters can end both well and badly. Friendly duel. Press F.
In fact, both Yaschur and Revan are right in their own way. All of Revan's arguments are clear, and at the stage of "pay 500 coins and you will definitely get the item," it is obvious that it was not trolling. Plus, Revan explained in more detail that there were options, but they were not easy. And yes, it is logical that unfamiliar random players may be refused their requests by merchants and masters.
I can still understand Yaschur. The first character, he put his soul into it, worked out everything, wrote down the principles and followed them, even if they did not match the current world in some ways. This is good because he developed the personality, got into it, and remained it until the very end. Even if it cost him a beating with a complete loss of items, many really ended up dying. I'm very sorry that because of an unsuccessful experience, he formed the opinion that there are "favorites" among the players in campaigns, and now he doesn't even want to try anymore. Although Revan does have some additional sympathy for well-written characters with cool roleplaying, as he himself said almost directly. But I don't think that's so bad. Worthy roleplaying is always a response to the GM's work.

