Mnemae Longstride
by David S. LelandMeet Mnemae (neh-may) Longstride, a woman famous for her amazing, seemingly limitless memory for what is told to her. She makes her living by travelling from city to city receiving and delivering messages verbally. In a small country, this could be on foot. If you want it more cosmopolitan you can upgrade to a horse, or further to a flying carpet or flying mount. Teleport makes sense but is too easy and boring, and because of the speed, makes the memorising aspect less impressive.
Mnemae charges a standard price for publicly announced messages, based on the distance between cities/towns. She comes walking (or riding) into your town, announces her arrival in the town square, and calls out the time next morning when she will deliver the messages. She stays at an inn overnight while the news of her arrival spreads. The next morning, she recites the messages like a town crier, and anyone knowing/hoping they have a message for them, or wanting to have one delivered, stands around in a crowd waiting. A popular custom is for friends or relatives to send messages with a humorous component that may poke fun at the recipient, since it is known that others (particularly peers and other family) will be present when the messages are delivered. Mnemae then accepts new messages.
While this service is largely a form of entertainment and known to many, very few people know that for a more substantial fee, Mnemae will personally deliver a message to someone in private. She sometimes makes these personal deliveries after the general ones, but more often she dons a disguise before arriving in town and distributes private messages first, then re-enters the town as per normal and gives general messages. This is to foil attempts at tailing her after the general announcements to see to whom she's delivering private messages.
Especially among the more powerful and wealthy clients who use the private delivery method, she is renowned for her Neutrality and non-involvement in political affairs of any sort, and is trusted not to reveal information to others. Some give her messages in codes and riddles, more to keep others from getting information out of her than out of fear that she may sell out. Furthermore, she seems to have a natural resistance similar to that conferred by a Medallion vs. Crystal Balls and ESP or other magic item, such that tracking her or prying into her mind magically is next to impossible, increasing customer security. Clients like the fact that there is no physical evidence of any message.
Many people speculate that she is a magic-user of some sort, or that she has some sort of gimmick (even as simple as writing down the messages in private soon after she receives them), but the truth is that she is just a normal human (or non-spellcaster at least, perhaps a low-to-mid level thief/rogue) with an "audiographic memory." The immunity to magical probing could be the result of some blessing, having an ancestor of some strange race, or even part of the same natural gift that gives her the amazing memory. As the DM, you are under no obligation to explain to your players--stranger things happen.
PCs may be familiar with Mnemae from seeing her receive and deliver messages at the centre of their town. Perhaps they have sent or received messages from her in the past. Here's an adventure hook: a detective/rescue mission where Mnemae turns up missing. A client wants to know what happened to her because he paid her to deliver a very important coded message. It turns out she's been kidnapped and some villain is keeping her prisoner and interrogating (i.e. torturing) her until she reveals the message, which contains information that will play into his dastardly plans. Because of her immunity to magical interrogation, it will take time to get the information out of her. The PCs must hurry!
When they rescue her, they learn that the original sender is missing or has been killed in an attempt to capture or interrogate him, and now Mnemae is the only one known to know the message. She accepted a Geas which prevents her from transmitting her message in any manner other than verbally to the recipient (i.e. can't write it down or tell anyone else), so the PCs must escort her to her destination quickly before she forgets enough details of the intricately-coded message that it becomes "ruined." All along the way, thugs and assassins attempt to recapture or kill her, and party must defend her at all costs. When she is finally rescued and the message delivered, the content of that message may lead into your next adventure...
Magus Coeruleus