Rachel's recklessness develops into disturbing, violent, sometimes sadistic, tendencies during the series. She is frequently described as "addicted" to the "rush" of the war -- the feeling of battle and conquering her enemies -- more or less, an adrenaline junkie. Rachel is brought face-to-face with this part of her personality in The Solution and The Separation and struggled with it through the rest of the series, never quite getting back to becoming a "normal girl". In the last book Rachel is sent to kill Tom. She succeeds in doing so, but in the end she is killed by some of Tom's minions. When Jake, Marco, and Tobias set off to go save Ax, they name the cruiser-class ship they board in The Rachel in her honor.

Her last name is not known for certain, but many assume that it is Berenson, like Jake's. (Which would make her Jake's cousin on his father's side.) It is stated in Megamorphs 3 that Rachel is half-Jewish on her father's side, as is Jake, and when a mutual cousin appears during the David trilogy (Animorphs #20-22), it is mentioned that they have not been close to Rachel's family since the divorce and her dad moved out. Also, Rachel is not invited to Grandpa G's funeral-- Jake's mother's grandfather-- in Animorphs #31).

Rachel is also a very prominent figure in fanfiction, and quite a few stories involve her death and/or resurrection (often thanks in some manner to the Ellimist).