Establishing some rules for Slenderman and other monsters

[Moose Fisher]

I've been tossing around the idea of a World of Darkness game/campaign/chronicle/whateverfancyterm with Slenderman.  I'm planning on using it more as a narrative force than a big beastie.
The idea would be the characters encounter Slenderman or something related to it, and become marked by its 'hunt'.  This would then lead to the characters spending the rest of the sessions trying to delay their capture in some way.  They'd likely spend time gathering information, talking with 'survivors' and the hunted, thwarting whatever is related to Slenderman, and maybe some things on the side (this is the World of Darkness after all).

While the motivations and abilities of Slenderman are nebulous, I've decided to set down some rules.  This will allow the players to have an idea when they're in trouble or relatively safe.  This will also give me some ideas for scenarios.
I've already decided to place Slenderman as one of the True Fae, as I want to stick to roots of folklore some have given it.  This will also give the rules greater strength and reason.  As a True Fae, this means Slenderman is going to be weak to Cold Iron and ruled by some kind of vice.
EDIT: This will also give me the excuse to toss in some stuff from Changeling as a way for captured characters to return.

As for his other rules and qualities:

• Slenderman capitalizes on the unreliability of human memory.
• The iconic association with fire, water, and the woods.  Don't go in the woods!
• "Slenderwalking" -- Observation makes it hold still, but doesn't stop it from using powers and arms.
• Interference with recorded media and electronics.  Our technology counters Slenderman preying on unreliable memory.
• Creating confusion and memory loss.
• Symbols do act as wards, but lose effectiveness and can be overcome.

I'd like some additional ideas, mostly to explain how the characters can keep running and not get snatched up instantly.  Other interpretations of Slenderman would provide some good fuel as well; I could toss them in as red herrings.
And to open the topic up to things beyond Slenderman: what kind of rules have you created or encountered for the entities in your games?

[Review Cultist]

Ive been dabbling with the concept that Slenderman is an aspect of fear or a manifestation of it. As a result when it gets really close, or even makes contact, there is a strong chance the victim is overwhelmed by there greatest fears, which causes insanity or paralysis.

[edwardian_adventurer]

I just started a Slenderman game that draws from Changeling. My idea for Slenderman is that he is a True Fae who was actually banished from Fae society. He was originally part of the Autumn Court and derived a lot of power from fear. Rather than enslave humans for service or entertainment, he performed experiments on them, turning them into puppets that he was able to control Eventually, the lords of the Autumn Court banished him. He fled into The Hedge, where he has hidden and continues his work in secret.

For the monster itself, the man in a suit is how he appears among humans; he found long ago that his true form (one that was corrupted by the magic he used) was disturbing to the human psyche. It was hard to lure his victims to The Hedge if he looked too unusual. He has found that children are the best subjects for his experiments. To this end, he has been abducting children from a small town in Kansas. Because I wanted to do a game with Black Eyed Kids, I decided that the BEKs were actually the victims of Slenderman. He returns them to look for more test subjects.

Additionally, the Summer Court is hunting Slenderman. They disagreed with the Autumn Court's decision to banish him, feeling it would have been better to execute him outright. Essentially, I want the players to avoid a direct confrontation with Slenderman, instead striking a deal with the Summer Court to follow the BEKs and find Slendy's hiding place. The Fae will take care of him, thus keeping Slenderman a mysterious character.

No telling if the players will choose to do this, however.

[Moose Fisher]

I haven't sat down to write any more stuff, but I did recall another good source of inspiration.

If you've played Amnesia: The Dark Descent, the main character is being chased by something known as the Shadow.  It serves as a reason for why the character can't leave and also gives a sense of urgency when the tell-tale signs of the Shadow appear.

If I can do that with Slenderman, than things will work well.

I also found a file of all the old stories from the early days of Slenderman from SA and other sites.  http://www.mediafire.com/?ayru5dep5q7cc9k