An RPG engine designed for fast and flexible play in adventures where darkness and equipment matter
The foundation of Cthonic One Roll is inspired by the excellent One Roll Engine by Greg Stolze.
Cthonic One Roll does away with each character having separate stats and skills. Instead, each character has a number of cards which each represent a single ability. The abilities can be vague (Persuade) or specific (Poison the Wine). Each ability has a number of dice slots on it, and sometimes restrictions on what dice can be used in those slots. For example, one ability might have three slots with "All identical" which means that it can be activated by three dice showing the same number. As abilities are used, the dice used for them are placed into the dice cup for that character, making the visual of running low on dice represent a timer for the players.
At the beginning of a scene change, each player takes the collected number of d6 they have for their character (both ones in the dice cup and ones left over from the previous scene), and rolls all of them at once. For the duration of that scene, those dice and their results are the sum total of what that character can do. Once a character runs out of dice (or can't assemble them into an ability usage) that character can no longer take actions in the scene. This provides a natural cap to the length of a particular scene, preventing the combat-takes-forever problem common to many RPGs.
In each scene there is also a Light level. Light determines what the maximum number on each used die can be. For example, a Light level of 3 means only dice showing a 1, 2, or 3 can be used for abilities.