Improved Energy Resistance
( Races of Faerun, p. 164)[General]
Choose one form of energy to which you have a natural (not spell- or item-granted) resistance. Your inherent resistance to this kind of energy is more effective than normal.
Prerequisite
Naturally resistant to a form of energy (acid, cold, electricity, fire, sonic),
Benefit
Your resistance to that type of energy increases by 5. For example, if you are an aasimar, you normally have acid, cold, and electricity resistance 5. You could use this feat to increase one of those resistances to 10; the other two are unaffected.
Special
You can gain this feat multiple times. Its effects do not stack. Each time you take the feat, it applies to another type of energy to which you have a natural resistance.