Mephisto brings about the projection onto the anima with its tragic end (child murder). There follows the suppression of Eros by the power drive (Walpurgisnacht = overpowering by the shadow).
Jung’s alchemical reading of Faust maps Mephistopheles, the anima projection, and the shadow’s suppression of Eros onto a systematic individuation schema governed by the quaternary axiom of Maria.
, Collected Works Volume 18: The Symbolic Life, 1976thesis