Those are small and agile, translucent magical creatures. They are tiny and physically weak (one size lesser than a gnome). They cannot wield weapons heavier than 4 pounds.

Due to their magical nature, they are:
1. Resistant to magic;
2. Have bonus -svs spells (-50 svs spells);
3. Permanently translucent (permanent pass door and probably protective shield, though this is maybe OPed);
4. Have permanent strong bonus to spellcraft (similar to light armor warpriest, but more potent);
5. Vuln_negative;
6. Vuln_steel.

Their primary stats are:
str 14 dex 21 int 25 wis 23 con 15 chr 20

Faeries can become any mage (except for necromancers) and also druids (exception from the rule that druids are always neutral - this is why they would be valuable - fairy + druid = dryad).