Luck in Fantastic Heroes & Witchery
Among the mechanical innovations of Dungeon Crawl Classics is the Luck stat. Here Luck is an Ability score like Strength or Intelligence, and is a useful tool for GMs to impartially determine a character's fortune. But what really makes Luck great is the rule that allows players to spend points of Luck to increase die rolls.
Because spent Luck recovers very slowly (if at all) it acts as a diminishing resource. As the character spends Luck to survive immediate dangers and overcome challenges, the foreboding sense of future doom tangibly grows, and it does so as a direct result of the player's own choices. It's brilliant. I don't believe it's a coincidence that a very similar mechanic was introduced into Call of Cthulhu 7th edition.
Here's my adaption of Luck for Fantastic Heroes and Witchery.
Luck (the 7th Ability score)
Spending Luck - A PC may spend Luck points to increase the result of an attack roll, saving throw or skill check, allowing him to succeed where he would otherwise have failed.
Regaining Luck - PCs regain one point of Luck at the end of each adventure. Upon gaining an experience level, a PC regains a number of Luck Points equal to his Charisma Bonus + 1. Finally a PC may also regain Luck for performing acts of great heroism, at the GM's discretion.
Luck Check - Roll 1d20, if the result is equal to below the PC's Luck score, he is successful. Luck Points cannot be spent to increase a character's chance of success on a Luck Check.
Luck Modifier - A character's Luck modifier is determined at character creation and does not change as a result of spending Luck. Roll 2d6 to determine what is modified by a character's Luck.
2 - 4 ..... All Skill Checks
5 - 7 ..... All Saving Throws
8 ..... Missile Attack Rolls
9 ..... Melee Attack Rolls
10 ..... All Attack Rolls
11 ..... Armor Class
12 ..... Roll Twice