Arima beneath the earth, grim Echidna, a nymph who dies not nor grows old all her days. [2] Usually considered an offspring of  Tartarus  and  Gaia , or of  Ceto  and  Phorcys  (according to  Hesiod ) or of  Chrysaor  and the  naiad   Callirhoe , or Peiras and  Styx  (according to