Let's put it this way, in the Campaigns, Zehir said that after Marquel's spell, he could no longer be resurrected. But what that spell was remains unclear; I couldn't find anything like it in the spellbook. Apparently, this was an artificial device used by the developers to cut off that storyline, but nevertheless, I decided to revive it. Perhaps the First in the Circle didn't approach his task with enough zeal, or maybe he just said it to discourage anyone from even attempting to resurrect Marquel, so that later Fagus would come along, try, and succeed. In any case, this isn't so important to me; what matters is what it led to.
And it should be noted that this is really just my fantasy, with a certain amount of humor, as has been observed. If you think it deviates from the canon, so be it, but how can one objectively assess whether it also has the right to exist? In the future, if I overcome my laziness, I plan to deviate from the canon a couple more times in my maps (of the same kind, that is, not rewriting history, but slightly reinterpreting events from a different angle), because otherwise, there are things that don't quite fit together.