You may also allow heroes to use the Mithral Forge to craft magic items that are not part of the Mithral Forge Recipes. Such items keep their standard gold costs and time requirements per rarity (Game Master’s Guide), while the forge and its characters act as special skilled hirelings (Player’s Book). These skilled hirelings have proficiency in every tool and can act as multiple concurrent assistants over one item, but require a higher amount of gold per day of work, following the Crafting with the Mithral Forge table.

For example, a Rare magic item usually requires 50 days of work and 2000 GP to be crafted. If the Mithral Forge is used to its full capacity (Baseline Speed, Mithral Forge, Volkan’s Assistance, Steros’ Assistance), this means that there will be 4 total assistants crafting the item for 200 GP per day of work, bringing the required time down to 12 days (50 days divided by 4 assistants) and costing an extra 2400 GP (200 GP times 12 days).