In the subrule Stockpile, add a Material named Ore with a Defense Factor of 3.

In the subrule Tasks, after “and a number of Serfs.”, append “These Serfs are considered to be Assigned by the corresponding Vassal. Unless otherwise stated, a Task’s Effect applies to each Vassal based on the number of Serfs Assigned by that Vassal.”

Add the following Tasks to the table of Tasks:

Chop|Gain 1 Wood for each Assigned Serf
Dig|Gain 1 Stone for every two Assigned Serfs
Mine|Gain 1 Ore for every three Assigned Serfs
Smelt|For each Assigned Serf, spend 1 Ore to gain 1 Iron

In the rule Serfs, after “defaulting to 5.”, append “As a Virtual Action, a Vassal may Assign their Serfs to one or more Tasks, replacing any previous Assignment. If they Assign fewer Serfs than they have, any remaining Serfs are considered to be Assigned to Idle.”

Add the following step to the Fortnight atomic action before “Charge a Wave”:

* For each Task, apply its effects to each Vassal that has Assigned at least one Serf to that Task.