Built for Call of Cthulu 🐙 role playing games 🕵☠️🙀
Bonus and Penalty modifiers only apply to d100 rolls, where an extra d10 would be rolled; the final result is the lower (bonus) or higher (penalty) value of the two d10 rolls.
To see the source code, add '/_src' to the end of the url, or browse the project on Github.