3e SRD:Psionic Body
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Psionic Body [Psionic]
Benefit: At 1st level, the character may use his or her key ability modifier determined by his or her primary discipline, if a psion, instead of his or her Constitution modifier to determine bonus hit points. At higher levels, the characters bonus hit points are determined by his or her Constitution, as normal. However, the character now gains +1 hit point every time he or she learns a metapsionic feat.
Special: A character may only take this feat as a 1st-level character.