After her break up with Nate, Cassie will become the
Big Bad Ensemble with him and Laurie in Season 3 where she plans out her revenge spree against her former friends.
Knowing how much deranged Cassie has become, Nate breaking up with her was the last straw for her sanity. It's possible after attempting to physically abuse Lexi and ruin her play to spite her, she will give a similar "The Reason You Suck" Speech Rue gave to Jules, but to both Lexi and Maddy, telling them that they're dead to her and will tell Maddy to go and kill herself if she wanted the madness with Nate to end because the world would be better off without her and it's her fault she angered Nate. Cassie even wishes that Lexi should've been miscarried or a stillborn because Cassie feels sick looking at both the girls and blames them for ruining her life.
It's possible Cassie will plan out a vengeance rampage against Maddy, Rue and Lexi where she will ruin their lives and break them mentally. She will be enraged finding out that Nate was obsessed with Jules and knowing Rue used to date her, she will target Jules in order to hurt Rue and team up with her former dealer Laurie to help her destroy Rue's life.
The fate of the third Jacobs family sibling
The audience sees a photo of the Jacobs family consisting of Nate, his parents, and two siblings. Thus far, we have only seen one of Nate’s siblings - Aaron - while the other one is conspicuously absent. The photo appears again in season 2 where Cal takes the photo down as he is criticizing his family. It’s quite possible that this third child died in childhood, which only contributed to the fracturing of the Jacobs family unit (which wasn’t strong to begin with), and the family is trying to ignore it in order to preserve their “peaceful” All American family image.
In Season 3, Cassie will try to kill either Maddy or Lexi, but Rue ends up sacrificing herself by coming in between to save them and Cassie stabs her in the stomach and wounds her. Rue survives though
Cassie might use Nate's family and their lawyers to bribe the high school into letting her off the hook for her actions at Lexi's play and get away scot-free without any consequences, similar to what Nate did to get away with his assault on Maddy during carnival.
