First off, Mites are 1/4 CR and their "monster role" is "combat".
I think that technically each PC class level increases the CR by 1. So a Mite who has one level of fighter, is CR 1 1/4, and the fraction is dropped, so I think CR 1. On the other hand, a non key class like rogue would only add 1 to the CR per two class levels. So I think you could have a mite with 1 level of rogue who is still only CR 1/4, but the next level would bump the CR up to 1.
I would say that the "rules" for determining CR is more of a suggestion. I'm under the impression that they were designed for adding levels to tougher creatures, not fractional CR monsters. Build the creature as you would for adding class levels to any creature with racial HD - Ability score bonuses, equipment, all class benefits, etc. Then take a good look at how it compares to similar monsters to determine CR.
EDIT: I think rogue is the most intuitive fit for mites, with ranger being a close second. Some sort of vermin druid is also a good fit. The are oddly well set up to be monks, which is unusual for fey. Due to low Int and Ch, they don't take to arcane classes as well. I would also be inclined to stay away from the heavy armor classes.
Kobold Cleaver wrote:
This may be indicative of something I should be worried about.
You know what you should be worried about? Gnomes! With their stupid tiny eyes... Pitoooy! I say!
You know what is even more strange to stumble upon? Trolls! I found this place on a long trip, and it was really odd to stumble on.
Comrade Anklebiter wrote:
Checks Beastiary - Goblins - 10 Int score. Sorry, can't blame that one on race. You Goblins ain't so bad. Now us Mites, we bad at math with our 8 Int. But damn, you goblins got 6 charisma! That makes a kolbold look klassy!
Just add one of our Pugwampi "friends" and we might just pull a TPK on your six friends...
Make use of the height advantage, and the mites climb speed. Rickety ladders and tight openings work well for mites, less so for larger races.
Also, giving a few mites a level or two of rogue, druid, cleric, or whatever will go a long way toward making it an exciting combat.
Finally, go crazy with the alchemical items. Tanglefoot bags, thunderstones, acid flasks, etc.
Scored a racial HD! And a d6 at that! Suck on that you d4 kobolds!
What? the Kobold in the book has a d8? Damn it!
Ok, ok, so what did get for 1 HD of Fey... proficiency with all weapons? Crazy immunities? True seeing? Breath weapon?
Ok, here it is...
A fey is a creature with supernatural abilities and connections to nature or to some other force or place. Fey are usually human-shaped."
That's it? I wanna be a plant or undead or something!