Tome of Horrors Compatibility

Product Discussion

I am new to Pathfinder and just starting to read the very beginning of the core book. One thing that I liked about the introduction text was that they stated that Pathfinder aims to be compatible with existing D&D material (i.e. 3.0/3.5). That's great because I don't yet have the Pathfinder Bestiary, but I do own the pdf copy of The Tome of Horrors and the hardback copies of The Tome of Horrors II and The Tome of Horrors III. So, I immediately thought there should be no problem using them based on the core rulebook assertion of compatibility.

However, now I see that Necromancer Games has published a Tome of Horrors Complete book that is supposedly updated for Pathfinder compatibility. So I find myself scratching my head and wondering why they needed to do this if the original material is already supposed to be compatible?

Can anyone tell me just how compatible the original 3.0/3.5 material is to Pathfinder? What kind of drastic changes should I need to make in the original Tome of Horrors material to use it in my Pathfinder campaign? If there is a place where all this is explained then that would be great.


I don't own the Tome myself, but the 3.5 and 3.0 stuff won't contain the Combat Manuevers Attack and Defense numbers, which are easily calculated off the cuff.

The monsters themselves will probably be slightly weaker than you would expect. Pathfinder characters tend to have slightly more skills and hp as well as big boosts to martial characters.

The nerf to the save or die spells won't really matter to you since its an across the board thing.

You should be fine, just be aware some skills were merged between editions. Like Spot is in Perception, Concentration is in Spellcraft, etc.

Edit: Most adventures should be simple to convert. The Role Playing won't change much, and you can easily grab the updated monsters from the online System Reference Document since most Pathfinder stuff is Open Game Content.

Pathfinder Adventure, Adventure Path Subscriber

Pathfinder and 3.5e aren't identical. Compatible, yes, identical no.

For instance: creatures in Pathfinder get feats at every odd hit die, where in 3.5e they'd get feats every three hit dice. So you can use a 3.5e monster manual, but recognize that those monsters can be "missing" feats. Not hard to ignore or on-the-fly address.

For instance: skills are more consolidated in Pathfinder. You'll find monster statblocks from 3.5e reference Search, Spot, and Listen where in Pathfinder those are all just Perception. Again, you can use a 3.5e monster manual, but just on-the-fly adjust a few skills.

For instance: the combat maneuver system was completely rebuilt in Pathfinder. You'll find 3.5e monsters reference a Grapple stat. That doesn't exist in Pathfinder, where you have a CMB/CMD set of stats. Those are very easily calculated, so you can use a 3.5e monster manual and just on-the-fly adapt to the CMB/CMD system for grapples, bull rushes and so on.

For instance: classes in Pathfinder get something every level. There were a lot of "dead levels" in 3.5e where you'd get very little. Perhaps your BAB and saves went up, or you got a spell slot. Hardly exciting. Pathfinder added things like rage powers, rogue talents, sorcerer bloodline abilities, and cleric domain abilities to fill in those dead levels. You can use a 3.5e monster manual, but classed monsters will be missing those little filler features. It's very minor and easily ignored, but it's there.

That's a summary for you. The two systems are very, very compatible but there's still some minor tweaking involved. On the other and, using 3.5e material with 4e just doesn't work. Everything got rebuilt and abilities power-scale were remapped, so you'd have to basically rewrite everything from scratch.

Think of Pathfinder as 3.75e 'Cuz that's pretty much what it is. Good luck.

some of monsters rules did change, from 3.x to pathfinder as well as hit dice used and skills and xp is different. all creatures are worth static xp now, based on their cr. you have to be 10 levels over something before it does not give you any xp, while in 3.x i think it was 4 or 5 levels. even then if your 10 levels over a creature the amount of xp it gives you is so small based on what is required to level. it not going to affect the outcome if you do or do not give it to the pcs. ability scores maybe slightly different now also as are DR functions. creatures have more feats now in pathfinder version. So while you can use the old tomb of horror, you may have to make a few manual changes as some monster will be strong or weaker based on cr and these changes.

The biggest ones are increasing the number of feats and skill monsters have and adjusting immunities and adding in cmb and cmd functions now to them, like undead and constructs are no longer immune to sneak attack and critical hits. Someone correct me but I believe undead where originally immune to cold by default unless otherwise stated. Now they are not. Also undead are reduced to d8 hit dice from d12, but treat Cha mod as con now. Animals where nerfed big time by pathfinder cr wise. A T-rex cr was a lot higher in 3.x then it is pathfinder.

I think originally they were not expecting so many changes but as more pathfinder books came out more issues end up showing up so they fixed the books they had. Pathfinder was a 3.5 system also for a little while, the first 3 or 4 Adventure paths where all written in 3.5. until they decided to come up with their own rule set.

The fully converted books cleaned up all this extra work a gm would have to do on his own and actual added a few things.

You can use the pathfinder PRD or to get access to monsters free from the web.


Anguish wrote:
For instance: creatures in Pathfinder get feats at every odd hit die, where in 3.5e they'd get feats every three hit dice. So you can use a 3.5e monster manual, but recognize that those monsters can be "missing" feats. Not hard to ignore or on-the-fly address.

My general "on the fly" method is to just leave the monster completely as-is (computing CMB and CMD if I need it), and reducing CR by 1, sometimes 2. Overall, that worked OK when I was in the process of "cutting over" from 3.5 to Pathfinder.

As I have both, most monsters are ok to use the old, but some like undead and dragons are quite different. Undead has already been mentioned, dragons were nerfed in many ways on hit dice in pathfinder. I would recommend updating. It was the first pathfinder book I bought and in fact bought it before converting over to pathfinder.

Thanks for all the advice. It helps a lot. For now I think I'll just trudge along as I learn the Pathfinder rules more and see what needs tweaking, modifying on-the-fly as I get deeper into it. I realize now that I also have a few stock D&D 3.0/3.5 Monster Manuals that I can use. I'm going to be house-ruling some things in Pathfinder that may also make it easier for me to do any conversions.

Layout and Design, Frog God Games

You might also want to check for specific monsters on

We updated all three Tomes of Horror to "Tome of Horrors Complete" and those updates are available there.

Thanks for the tip. Comparing the stats there with the book stats will help me see the differences quickly.

Silver Crusade

There is also a document that Paizo put together for converting monsters from 3.5 to Pathfinder back when they first released...

You can find it under Pathfinder Roleplaying Games Resources. Title of the document is "3.5 Conversion Guide".

Pathfinder Lead Developer, Frog God Games

Thanks, tempestorm!

I have the Pathfinder Tome of Horrors Complete. In the preface it seems to imply it's just the same Tome of Horrors with those conversions done plus a couple extras for wholesome goodness. Following that you should be fine.

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