Using Existing Mechanics
The first, and often easiest step, is to identify abilities that can be covered with existing game mechanics. Take your list and starting looking for abilities that are already covered by feats, spells, or special abilities from other classes. I generally find that at least two or three of my abilities have already been created and I just have to find a way to integrate them into the class in a logical and balanced manner.
If your special ability can easily be duplicated by a feat, go ahead and add it as a bonus feat, generally without the need to meet the prerequisites. I would recommend that you duplicate no more than two abilities in this manner, as feats are generally a fairly uninspiring and lackluster ability for a prestige class.
If your special ability can be duplicated with a spell, you have two options. If your class is not a spellcasting class you can grant the spell as a spell-like ability a number of times per day, generally once or perhaps once per two or three class levels, depending on how important the ability is to the concept. Given the number of spells now in the game, a lot of abilities can be created in this manner.
If you would like to avoid giving the class a spell-like ability, instead look at the mechanics of the spell and re-write them as a supernatural ability. Unless you have a very good reason I wouldn’t grant this ability until the same level that spellcasters get access to the spell. This prevents you from inadvertently granting a class a power beyond what it should have at a certain level.
If the class actually gains levels in a spellcasting class, you can add the spell to the class list (if it doesn’t get the spell normally), add it to their spells known, or simply give them a bonus spell slot useful for only casting that spell. Again, try to avoid granting this spell before it can normally be cast by a single class spellcaster.
If your special ability already exists in another class, whether a core class or a prestige class, it’s as easy as adding it to the class at an appropriate level. Try to avoid stealing more than one or two abilities in this manner, for if you’re just stealing abilities from a bunch of different classes chances are your class is either overpowered, too versatile, or simply too similar to an already existing class.
Creating New Mechanics
Once you’ve added special abilities from existing mechanics, you now need to create new mechanics for the abilities that you have left. Unfortunately, there is not a tried and true formula or method for doing this. Creating a new mechanic is as much art and intuition as it is a science, so be prepared to draft a lot of revisions.
The first step I follow is finding an existing ability or mechanic that most closely matches what I would like to accomplish. It’s generally easier to modify and existing mechanic as it is to craft a wholly new mechanic, so starting with an existing ability is the best method. Given the number of mechanics found in the game it’s a fairly good bet that you can find something that at least partially matches what you want.
Beyond adaptation of existing mechanics, there is very little I can suggest for making wholly new mechanics. All I can do is give you my own process, which may or may not work well for you. To start I simply write down a description of what this ability does, completely ignoring game mechanics entirely. I try to get the wording down to a sentence or two, writing some basic flavor and the results.
Once I have my basic description, I then start looking at the numbers. If it affects the user of the power himself, I try to figure out what sort of bonuses it should grant. Generally these will be bonuses to armor class, saving throws, attack rolls, or other hard mechanical benefits. When it comes to assigning numbers, a +2 bonus is generally a good place to start from. You can adjust the number upwards or downwards during playtesting.
If the ability affects someone else or an object, I start looking at what changes are made to the target and what the most appropriate saving throw should be, or if the chance can even be resisted (irresistible abilities should be very rare). A good rule of thumb for save DCs is generally 10 + appropriate ability modifier + class level (or equivalent spell level). If the effect does damage, start with 1d6 per class level and work from there, again adjusting the numbers during playtesting.
If the ability doesn’t affect the user or another target, it should generally either be handled with roleplaying or in the fluff of the class. Ask yourself why you are even adding this ability if it doesn’t have any hard mechanical benefits, since it’s likely that you can cut out this ability and add something else.
Placing Special Abilities
Once you have your special abilities crafted, you need to figure out where to place them in the class progression. Again there are no hard and fast rules for this, only common sense and a few suggestions beyond least powerful to most powerful in progression.
I generally grant bonus feats in the first few levels of the class, as they’re often the least powerful of the special abilities and make for good entry level shticks. If you have abilities that get progressively better as the class advances, try to grant them earlier so that players can see their bonuses grow over time. I suggest adding progressive abilities at 1st, 2nd, or 3rd level and no later than 4th level.
If at all possible, make sure that the class gets something each level on the class line. Even if it’s an improvement to an already existing ability, give them something. There is nothing worse than a class filled with a lot of dead levels, as players don’t see any tangible reward for advancing a level.
Spell-like and supernatural abilities should be granted at the same or later level that spellcasters get access to the spell that the ability is based upon. I prefer to grant them one level later than a pure spellcaster, unless the ability is a cornerstone of the class. Under very few circumstances should a class gain access to a spell before its intended level, as it will usually result in a broken class.
If you have an oddball ability in your list of special abilities that doesn’t seem to have any clear place in the progression, reserve it and use it to fill in a dead level or grant it at a midpoint in the class (3rd level in a 5 level class and 5th level in a 10 level class).
Filling in Dead Levels
If you end up with a few dead levels, try to craft a few minor bonuses to fill them in. Bonus feats, skill bonuses, or small non-combat bonuses are good for this purpose. They don’t have to be huge or earth shattering abilities, but they should be something tangible. The idea is to grant something at every level, even if that something is +2 to a single skill or a bonus feat such as Toughness. Just make sure these small bonuses fit the theme of your class.
Conclusion
I want to reiterate that creating special abilities is not a hard science and that you’re probably not going to get them right the first time. You should expect to spend a lot of time playtesting these mechanics and tweaking the rules until they work in a balanced and appropriate manner. It seems like a daunting and difficult task, but try to get your ideas on paper and starting playing with them. The only way you’re going to get them right is by playtesting.
As a final word on this subject, message boards (such as RPGnet) are wonderful for both playtesting and creating mechanics. Other posters can often give you insight and ideas that wouldn’t have thought of yourself and point out flaws in mechanics before you start playtesting. Never design in a bubble when you can design by community (with you at the top). You don’t have to take every idea, after all it is your prestige class, but you should consider the opinions and ideas of others.
Join me next time when we’ll talk briefly about our next step; playtesting. Then we’ll finish off this column with some advice on writing your fluff and getting your prestige class out into the world.
