The d666 is the basic dice roll of In Nomine. It consists of 2d6, plus a third d6 as a "Check Digit".
Generally, one can think of it as limbo; the relevant question is whether or not the 2d6 rolls at or below the "Target Number". For example, if the TN is 5, results of 2, 3, 4, and 5 are successes. Target Numbers are typically made higher by statistics and positive modifiers, and made lower by negative modifiers.
The odds of hitting at or below a given Target Number are as follows:
|TN||Probability of Success|
Target Numbers above 12 result in an auto-success, unless an opposed intervention is rolled, and add a point to the Check Digit for each notch they are above 12. E.g., a 14 is an auto-success with a +2 to the Check Digit.
- ↑ In Nomine Core Rulebook, p.38