They're constantly attacking Scott by sending robots after him to keep him distracted, making him more and more distant with Ramona as time goes on. What's especially interesting though is that the reader comes to know who the Katayanagis are throughout the book. They're technologically intelligent with their constant brigade of robots and their history with Ramona involves her cheating on them with each other. This volume's story revolves around cheating as this is the book where Knives finds out Scott cheated on him with Ramona, so the involvement of these Evil Exes allows for the story to explore this concept more than the film does as the Twins attempt to have Scott see her as an unfaithful partner. What's even more interesting is that Scott's fight with the Twins gives the story an opportunity to explore his past with Kim, the drummer for Sex Bob-Omb. Throughout the story, it's known that the two dated in high school for a while before he moved away. Now, tensions between them are pretty awkward as they continue to play in the same band, Kim constantly belittling Scott when she can. When Kim is kidnapped by the Twins though, she's actually cheering him on, trying to boost his confidence so he can defeat them and rescue her.
