Currently working on a campaign that is based in a horror base.
Each of the players start off with an imaginary pet that guides them. Most of the time the pet does really nothing, unless the player activates the creatures power(s)
The Pets I call Xualataurs, and the players each get one randomly after a certain event. Of course talking to the pet in public brings its typical views where no one else can see the pet.
The pet list..
Vic - Short for Victim. Vic looks like an pastel blue anthropomorphic fox... thing. The player who gets this pet cannot die. Horrible destructive wounds easily heal within a short period of time. Each time the player has to use this however, he instantly takes 5 points of sanity damage at least. (discussed later) The player has less HP than others and has a greater chance of receiving worse wounds..
After using the power to say, regenerate an arm (This is automatic, the player has no choice to not use the power unless he quickly does something before it kicks in), the arm will look like the imaginary pets arm. To normal people this still looks like a normal human arm, but other people can see it.
Bones - This one looks kinda like a cat or dog with a bone mask and a cloak covering the rest of its body. Its power is the ability to cast a basic set of necromancy spells. It has a secondary power to summon a powerful scythe that wracks at the mind. Unlike vic though, the player has a choice in using these, and a chance to save vs the sanity damage.
Whenever something with a Cr=1 or greater dies around the player, they have to make a will save vs 10+HD+cha of that creature or take that creatures cha mod in sanity damage (min 1) as they get a sudden rush of knowledge from the creature. Obviously though, this does not happen with mindless creatures.
Hanko - This one looks kinda like a dog who is always fairly angry with a single horn jutting out from its forehead. The player with this one gets various sorts of movement/teleportation spells. And suffers a -2 save vs emotion spells. They can maintain rage for 1/4 round per level longer than normal if they have it. (Using this power does not effect sanity) If they don't have it, they have the ability to use rage for 1 round per level, but in doing so they must make a will save every turn. (DC is 10+1*Rounds ranged+Hanko's Cha)
Tane - This one looks like a small ferret/cat. It has a third eye in its forehead and a pair of bird like wings. The player can cast various divination spells. The player can never become immune to fear and suffers a -2 save vs all fear effects. It has another power that is related in someway to seeing into the future and changing an event as a result, but I'm not sure what that would be yet.
Sharta - This one looks like a cat with mountain goat like horns and ears. It also has hooves for its front paws and bat like wings. Not sure what this ones powers and weaknesses are yet.
Boxes - This looks like a rabbit with a box like tower fro. Always vain, never without its mirror. The player can cast illusion spells, and has to try to maintain some sort of ideal appearance. As a result things that go against the appearance require saves, and being hit with any uglifying effect immediately requires a will save to prevent sanity damage. (Such as being covered in tar and feathers, or forced to disguise themselves as a hobo.)
Wound, Sanity, and Corruption.
For wounds a player has several "checkpoints" One at 75% health, 50% health and 25% health. As the player reaches these check marks, he rolls of the wound chart. At first level the player gets their entire con score to their hp. For just taking damage slowly, the player does get to make a fort save, but taking a blow that deals 25% of their health requires them to immediately roll on the lesser wound chart.
Sanity and Corruption however are a bit different. Every time the player has 5 points of damage the roll on the appropriate chart. Less if they they are under 25 damage, Moderate if they are at 26-50, Greater if they are at 51-75 and finally Deathly if they are above 75 in damage.
A person who takes 100 points of sanity damage becomes a vegetable, or a mass murdering psycho killer. if you take 100 points of corruption damage, you either turn into chaos beast, gibbering mouther or various other nasties. Or just simply die.
I'm looking for some feed back or more things to put on the charts. I want there to be somethings with a higher chance to get, but not everything be 5% chance you know?
I removed a post. Don't be a jerk.
Stuff like this can be interesting, but don't try to implement an overly complex system or the bog down with the rules can ruin it.
You probably have already, but have you looked at Ravenloft/Call of Cthulhu material? Most of those books have interesting ideas, as do their support communities.
My one real suggestion is that you don't try to force a 1-100 chart. Just do 50. Or 25. Give yourself more time to develop the core of what you are doing, instead of a set of charts that the players will try to avoid rolling on.
I'd recommend getting your hands on the WOTC 3.5 book Heroes of Horror, and/or the d20 Call of Cthulhu rulebook (both out of print, but can be found on the used book market).
HoH included a set of rules for "taint and corruption" as well as adventuring in dreamscapes.
The d20 CoC rulebook had parallel rules for Sanity and adventuring in the Dreamlands.
I try not to invent new systems on my own if I can lift someone else's ruleset. This lets me concentrate on plot and encounter design.
Good luck!
I like the imaginary pets part. The corruption 100 damage sounds like it could be fun, but i'm not too crazy about the wound rolling. It seems a bit complicated to me.