Ok, I know this has probably been discussed ad nauseam, but what's the best way to make a Monster PC?
Obviously, many monsters are more powerful than the base classes.
To compensate, some people suggest giving the Monster PC an experience debt or making it take levels in NPC classes, such as Commoner.
Here's my problem:
Paizo removed the Level Adjustment mechanic, so I'm not sure how to gauge the severity of the penalties.
So what's the best method for determining how to make a Monster PC equal to a base class PC?
Its going to vary from monster to monster, and what style of game you want.
Some (tiefling for example, since we have stats for them) you might let in at no penalty, or a very limited one.
Others, that have no racial hit dice, you might want to decide how much more powerful they will be than a regular PC, and then try and even the playing field. That could mean an xp debt, forced levels (I hate that one), or even boosting the other PC's gold allowance.
And so on. I think until Paizo can come up with a solid set of rules, we are left with coming up with the rules ourselves, probably on a case by case basis. All in all, its going to be a judgement call, based on your campaign, and your players, and what monster you are talking about.
Unfortunately, I don't know the monsters well enough to make accurate assumptions about how "good" they are.
Obviously, there's a big difference between bugbears and vampires and I want to make sure I adjust them accordingly.
I'm not a fan of guess work, so I can't wait until Paizo comes out with a consistent "by the book" system.
Do you think the Bestiary will have rules for this?
If you can get your hands on a copy of Savage Species, the same general principles hold - just use Pathfinder core races as a baseline, instead of the 3E ones.
No. They have said the Bestiary won't have rules for it.
And you don't need to compare monsters to other monsters. Compare it to the already presented pc races. Look at the monster as a race, and see how it stacks up.
And if you don't feel up to benchmarking it, post over in the homebrew or conversions part of the forums...lotta ways to get help there. Just say "What will I need to do to make (insert monster here) balanced in a party of (insert level of party here) if I allow it in as a character?" and see what you get.
Good advice so far.
Is the number of racial HD a fair representation of a creatures power and/or level?
HD aren't the sole judge, no.
Honestly, this is where, in my opnion, Savage Species (the 'monsters as races' book) failed utterly.
A monsters hit dice aren't always equal to a players in terms of bang for buck. Most people, when looking at them, tend to ignore that, and assume that because a monster has 3 hit dice (for example) that those 3 hit dice are equal to a PC's hit dice. For a monster that only has better stat boosts than PC's get, along with extraordinary abilities that are on par with what PC's recieve, with possible a slight natural armor bonus, I'd say they aren't getting the same bang out of those hit dice 3 levels of PC classes would give.
All in all, when you evaluate a monster for use as a PC, compare it to PC classes and races. Sometimes, you'll find a race that takes levels in PC from the get go (drow for example), that their abilities early on, are much, much better than the other PC's, but towards the middle and higher levels, aren't noticably better. So assess them a penalty that equalizes things early on, but fades away over time. Others might just be genericlly good at all levels (half ogres for example, as they were in 3.0/3.5), so assess them a more long term penalty.
While this doesn't quite go to determining what the Enhanced Character Level (ECL) should be this may be useful suggestion for actually bring such monster creatures into play earlier.
The Pathfinder Player's Guide for Council of Thieves makes some suggetsion on how to handle the Tiefling. One suggestion is XP debt, make the Tiefling pay a set amount more before actually starting to level up the first time.
For bigger monsters, like a Minotaur or even the older 3.5 Bugbear, this doesn't work so well because you don't want to front load the PCs with goodies, especially things like high-powered spell-like or high BAB from racial HD.
I know from working with Savage Species that trying to back build a Monster Class can be a painful process. I'm currently looking at a short cut using the PFRPG Negative Levels and the above mentioned XP debt. Add Negative Levels just short creature's total HD.
Again looking at the old Bugbear, add 2 Negative levels. Should end up just a slighly bit more powerful then the standard PFRPG races.
Example WotC Savage Progressions from 3.5 online http://www.wizards.com/default.asp?x=dnd/sp/20040213a