...Pardon? Can you give us a little to go on here? A particular region, culture, or piece of folklore or (dare I ask) piece of media / fiction / etc that's inspiring this question would help.

I understand your question being about the Hashishin and the fortress of Alamut (in modern-day Iran), is that correct?

(and I was going to suggest Umberto Eco's Baudolino as a possible pop-culture source for that, when I remembered that a certain video game series was a more likely source...)