Flavor and differentiating

[Xion_Anistu-san]

I am in the process of working on a campaign for my friends. They are very experienced and more than a bit devious. A couple of them are even RPGA-ranked DM’s. They all like “old school” D&D. I have several books that they don’t, so my question is this . . .

Is it OK for me to use classes, prestige classes, and magic from the books I have to give “normal” monsters a different feel or flavor in their encounters?

Example: I have the Tome of Battle and would like to give the drow warriors the group may encounter levels of swordsage or warblade with Shadow Hand or Stone Dragon techniques respectively. Is this fair to the party or would I be guilty of major cheese here?

[Jimp]

Yes, it would be very fair. Just remember to adjust the monster's CR. Generally, 1 class level = +1 CR.

[Golthur]

Absolutely fair. Having "new" stuff (or retooled "old" stuff) helps keep experienced players from knowing how to handle everything you throw at them (e.g. "Oh yeah, clearly that's an elder psurlon, it can use detect thoughts, mage armour, dominate person, ...").

Even if the players are good sports and keep character knowledge separate from player knowledge, it's still good to hit them with stuff that they don't know.

[Gralamin]

Yes, it would be very fair. Just remember to adjust the monster's CR. Generally, 1 class level = +1 CR.

Thats a good ruling. The RAW way is stupid.

Associated Class Levels

Class levels that increase a monster’s existing strengths are known as associated class levels. Each associated class level a monster has increases its CR by 1.

Barbarian, fighter, paladin, and ranger are associated classes for a creature that relies on its fighting ability.

Rogue and ranger are associated classes for a creature that relies on stealth to surprise its foes, or on skill use to give itself an advantage.

A spellcasting class is an associated class for a creature that already has the ability to cast spells as a character of the class in question, since the monster’s levels in the spellcasting class stack with its innate spellcasting ability.

If you add a class level that doesn’t directly play to a creature’s strength the class level is considered nonassociated, and things get a little more complicated. Adding a nonassociated class level to a monster increases its CR by ½ per level until one of its nonassociated class levels equals its original Hit Dice. At that point, each additional level of the same class or a similar one is considered associated and increases the monster’s CR by 1.

Say you have a CR 6 creature with 4 Hit dice. Lets say it doesn't have any spells. By RAW, Making it a Wizard 4 will increase its Challenge Rating by 2, And then every level after words is +1.

Similarly, lets say we have a 10 hit die creature, at CR 6. We decide to make it a Druid when it doesn't have any spellcasting. that means that We can make it a Druid 10, for a CR of 11, and then +1 for each additional class level.

Not only that, they automatically get the elite array.

When adding class levels to a creature, you should give it typical ability scores appropriate for that class. Most creatures are built using the standard array of ability scores: 11, 11, 11, 10, 10, 10, adjusted by racial modifiers. If you give a creature a PC class use the elite array of ability scores before racial adjustments: 15, 14, 13, 12, 10, 8. Creatures with NPC classes use the nonelite array of: 13, 12, 11, 10, 9, 8.

[hr]
On topic, it is fair.

[Tallis]

It's fair, but once they've been exposed to a new class they may look for a way to pick it up. Be prepared.

[Zincorium]

It's important to remember that you really shouldn't try to squeeze in more power for the same CR just because you can. I read an argument a while back on WotC's forums where someone claimed that the CR system was broken because they could build a vampire that could kill a party of five or so levels past it's supposed CR. This was, of course, challenged.

They then went on to explain how the vampire had multiple rounds to buff without a chance of being detected, lots of magic items, really high stats and a bunch of followers that had been harassing the PCs. Which of course should affect the CR. Thus the vampire was easily more of a challenge than the by-the-book CR would indicate.

CR isn't a hard and fast number. It's a guide. If something seems like it'll be more of a challenge, increase the CR. Not only does it give you a better idea of how busted up the party will be afterwards, but it gives them an appropriate reward in terms of loot and xp.

[Swooper]

You should definitely use those new classes and stuff. That's what it's there for. No fair if players can be psions, shadowcasters and crusaders if NPCs are stuck with adepts and warriors, eh? I'm designing a campaign setting myself, and I use all the optional classes I can (barring ToM, which I'm not too fond of and doesn't fit the campaign flavour).

[Tormsskull]

I'd say it depends. If they like "Old school" D&D then they may not like the idea of you using non-core books (like tome of battle). The group that I play with has been together off and on since OD&D, and I'd call us Old School, and we wouldn't be caught dead playing with 3.5 expansion books at our table.

If they are already familiar with what books are available/being used in the campaign, and they are cool with it, then I'd say you're all set.

[Kizara]

Two points here:

1) When you give a monster a class level, it increases its CR by 1. This has exactly 0 to do with HD unless the creature only naturally has 1/2 HD (such as drow). Do not confuse CR with LA, they have absolutely nothing to do with each-other.

2) Do they accept that source as usable material? If so, and the classes and abilities are reasonable in context (no drow clerics of pelor, etc), sure go ahead.
Do realize that if the enemies are more elite, able and powerful then normal, they should be treated as such RP-wise. Don't make random-smuck-scout guy a lvl 6 swordsage. Really build a character or group, give them a bit of flair and flavour.

[nerulean]

1) When you give a monster a class level, it increases its CR by 1. This has exactly 0 to do with HD unless the creature only naturally has 1/2 HD (such as drow). Do not confuse CR with LA, they have absolutely nothing to do with each-other.

Um, what? If you give a creature a class level, it's gets that class's HD on top of whatever racial hit dice it might have, and the total of the two count as the creature's HD for effects where that is taken into consideration, such as the Sleep spell.

Yes, HD, CR and LA have precious little to do with each other, but the way you've worded that seems likely to cause confusion.