Lovecraftean horror has reached peak saturation in RPGs. However, except for possibly The Yellow King RPG from Pelgrane, I don't see much new being done.
(Disclaimer: I haven't played loads, so if you know of some groundbreaking Cthulhu mythos RPG, leave a comment).
My recent Call of Cthulhu campaign, for all the fun, was a whirlwind tour of old fiction and gaming tropes. Nazis? Check. Time travel? Check. Dimensional jumps? Check. Alternate histories? Check. Ancient aliens? Check.
There were moments where it felt like we were pushing the envelope, mostly after we hit The Dreamlands, but they weren't enough. In this post I'll take off the chocks and see how far we can push the genre. I wish I knew enough of other rulesets, but I'll stick with the old fallback Call of Cthulhu (CoC), pre 7th edition.
COSMIC HORROR BENDS THE RULES
As the cosmic horrors bend and shape reality, so too should they bend and shape the rules. One of the things that got most tedious in our CoC game was combat, especially the myriad rolls to hit, defend, or do damage. Here is a table to return terror to combat by having damage done reflect the eldritch nature of mythos creatures.
1 Aging - Every point of damage is a year added to your age. Physical skills become capped at 100 - age, so if you are 66, your maximum physical skill becomes 34% (100 - 66 = 34).
2 De-aging - Every point of damage is a year subtracted from your age. Stats cannot exceed age, so for example if you are reduced to 8 years old, no attribute can be over 8. Skills are capped at relative attribute x 5%, so an 8 year old's skills couldn't exceed 40%.
3 Alienation - Damage is taken from your CHA. Maximum social skills (Persuade, Fast talk etc) are CHA x 5%. For example, if you have a Charisma of 3, no social skill can exceed 15%. If your CHA becomes negative, it is used as maximum value for a SAN damage roll. For example, if your CHA become - 3, you can do 1-3 SAN damage to someone who fails a Sanity roll when interacting with the soulless void you have become.
4 Withering - Damage is taken from your STR. Maximum physical skills (Climb, Grappling etc) are STR x 5%. For example, if you have a STR of 3, no physical skill can exceed 15%. A STR of 0 means you die from weakness, your body a strange limp jellyfish that incurs a 0/1 Sanity loss to behold.
5 Warping - Damage is taken from your DEX as your body is warped into horrific shapes. Maximum agility skills (Dodge, Dance etc) are DEX x 5%. For example, if you have a DEX of 3, no agility skill can exceed 15%. If your DEX becomes 3 or less, you are an invalid unable to stand. A DEX of 0 means you die from spastic convulsions.
6 Dulling - Damage is taken from your INT. Maximum knowledge skills (any science, language etc) are INT x 5%. If you have a INT of 3, no knowledge skill can exceed 15%. If your INT becomes 3 or less, you are a vegetable unable to control your body. An INT of 0 or less means you die from brain implosion.
7 Draining - Damage is taken from your POW. This affects Sanity and magic casting as per the rules. If your POW becomes 0 or negative, you become a ghost (see rulebook) and rise from the dead the next night to drain your former comrades.
8 Weakening - Damage is taken from your CON. A CON of 0 means you die from weakness. If your CON becomes negative, you become a vampire (see rulebook) and rise from the dead the next night to slake your thirst from your former comrades.
9 Shrinking - Damage is taken from your SIZ. This affects damage bonus done as per the rules. If your SIZ becomes negative, you shrink down to the Quantum Realm and have to battle its horrors. A TPK might spawn an entirely new genre of play.
10 Devolution - The strange energies from the horror knock you down the evolutionary ladder. Damage is recorded as normal, but when HPs reach zero, the character transmutes into a lower lifeform (1d4/1d6+1 SAN loss to witness). Keep INT the same but roll all other attributes as per the rulebook. New form is (roll 1d6)
4 giant squid
6 Keeper's choice.
The player can continue using the morphed character, but with logical limits (ie no human speech, lack of prehensile hands, need to be immersed in water, etc). The transformation incurs a 1/1d6 Sanity loss to behold.
11 Mutation - The strange energies from the horror change you into something... else. (roll 1d6)
2 Has a semi-transparent body immune to normal damage but taking double from mythos creatures.
3 Acquires movement that is out of step with reality, gains automatic dodge roll against any attack but fumble (00) means the PC slips into a crack in reality and is lost on other planes.
4 Becomes pale soul vampire, no longer requires mundane food but sucks POW for sustenance, needs 1 POW per day and an extra 1 for d6 healing.
The transformation incurs a 1/1d6 Sanity loss to behold, and 0/1 when seen thereafter.
12 Memory - Damage effaces your knowledge. Choose a random skill and take damage from that. There is a reason Level Drain was so feared in D&D it was nerfed in later editions.
4th Dimensional Horror