Complex sentence: There he finds Deckard, who reveals that he is the father of Rachael's child and that he scrambled the birth records to protect the child's identity before leaving it in the custody of the replicant freedom movement.
Split into simpler sentences: There he finds Deckard, who reveals that he is the father of Rachael's child and that he scrambled the birth records to protect the child's identity. He left the child in the custody of the replicant freedom movement.