Our main campaign will be played using the Dungeons & Dragons Fifth Edition rules by Wizards of the Coast.
Because I can’t help myself, I’ve made a number of changes to the rules, which you can browse here, to better fit the setting.
The short adventures will use the Old School Essentials rules, by Necrotic Gnome. OSE is a contemporary restatement of the original Basic and Expert rules of Dungeons & Dragons, from 1981.
In the classic old-school spirit, I have tweaked and adjusted some of these rules as well.