A Magnum Opus is a legendary project, requiring at least 50 weeks and around 50,000 gp to craft, with a resulting value of 100,000 gp. Crafting checks are made with a DC of 30. Due to the time and cost, most crafters will only complete a single magnum opus in their career.

Variant: To prevent progress towards very difficult projects early on, crafters must make the appropriate artisan‘s tools check for each week they wish to bank; only weeks with successful checks may be banked.

Once there are enough weeks banked, and the crafter has the necessary capital, they may make the final crafting rolls. To do this, they must make 3 checks: a business check, a check to try to read or manipulate their customers (likely insight, persuasion, or deception), and a check with an appropriate set of artisan‘s tools. Prior to making this check, they may choose to bank an additional 25% of weeks in order to make any one of these checks a second time, for a possible 4 total successes. Consult the crafting table to determine the multiplier. Multiply this by the project value to determine the total result of work.