The following house rules are suggested for a Hyborian Age campaign:
- Alignment: Characters, creatures and gods have no alignment. See the note about alignment for more information.
- Spellcasters: Some changes to the spellcasting classes are necessary to capture the feel of Hyborian sorcery.
- Starting age and aging effects are modified. Druids, shamans and sorcerers add four years to the standard starting age (for a total of 15+1d4+4 years). Clerics and wizards add six years to the standard starting age (for a total of 15+2d6+6 years). "Middle age" for humans in the Hyborian Age is 30 years, "old" is 45 years, and "venerable" is 60 years. Maximum age is +1d20 years.
- The only classes with automatic literacy are Cleric and Wizard. Starting characters of all other classes are assumed to be illiterate. Literacy can be bought by spending 2 skill points; literacy is then gained in all languages the character speaks (see the description of the barbarian's illiteracy in the PHB). Note that most (90%) of the people in the Thurian continent are illiterate.