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GameMastery Guide / Running a Game / How to Run a Game / GM Considerations

Converting Content from 3.5 or Other Systems

Source GameMastery Guide pg. 51
Roleplaying games have been around for over 30 years, and there’s a huge library of materials out there for other games which you can use in your campaign. One particularly easy conversion is from the 3.0 or 3.5 edition of the world’s oldest roleplaying game to the Pathfinder RPG.

The Pathfinder RPG was designed to be backwardcompatible with the 3.5 rules set. It’s possible to integrate the two seamlessly with almost no work; the only big difference in most games is that Pathfinder PCs are a little stronger overall than 3.5 PCs, so your PCs may have an easier time battling things from the old rules. You can run with that, or apply one of three simple fixes below to balance things out:

Reduce the CR by 1: Treat anything from 3.0 or 3.5 as 1 CR value lower.

Add the Advanced Creature Simple Template: Use the easy “+2 to everything” version rather than rebuilding all the old stat blocks.

Add Improved Initiative and Toughness: Pathfinder creatures get more feats than 3.0/3.5 creatures (every odd level rather than ever 3 levels). Adding these two feats for mid-to-high-level creatures helps make up the slight power difference between the two systems.

Of course, you can also look to other game systems for ideas and adventure materials, it just requires more work on your part. In most cases, searching the internet for fanmade conversion suggestions is a timesaver; most of these suggest skill DCs, replacement spells and magic items, and rough stat blocks or simple replacements (such as swapping the tcho-tcho people of the Lovecraftian mythos for goblins). Use the Pathfinder RPG rules as a resource— the Bestiary includes a wide variety of monsters so you can create the sort of fantasy that you want, and by trading a few proper nouns, you can convert even a superhero, space opera, or hard SF scenario into a fantasy plot.