As a DM I always try my best to include unique characters in my adventures. I wanted to use a lunatic character who has completely lost his mind as a sort of minor plot hook to introduce the players to a new part of the world. How do you think I could make the NPC believable, without revealing much about the mysterious place that he is from? What are some tips for role playing a character like this? What sort of voices could I use so that it is obvious to the party that he is insane?
I've had to do this before and have found it very difficult. As a result, instead of role playing the NPC, I've just described the NPC like, "While talking to you, he tends to frequently stray off-topic, speaking in several different languages, and referencing people and things that are not nearby. After a few minutes, it is obvious to all of you that this man is utterly insane. While it is difficult to decipher his train of thought, you hear him utter the phrase "[insert mysterious place's name]" several times."