Let's face it, rolling a 1 sucks, but adding realism to a dire situations make the game hilarious yet dramatic. There are rules out there saying that if you roll a 1, then another 1, you'll receive penalties. The chances of that are extremely minor, so I made a new system for critical fumbles. Everyone's natural critical fumble save is 10, this is lowered through Dex modifier. (Ex. +2 Dex means, you need a 8 or higher to pass instead of 10 or higher) Failure results in a very minor consequence. However, another natural 1 results in major consequences. 3 natural 1's results in something extremely dire and perhaps.... Fatal.
