A university calculus teacher who is considered a genius, Aldo is the other protagonist of the novel who struggles with his mental health and is drawn to Regan's complex nature.

Regan's former boyfriend who is manipulative and controlling, Marc struggles to accept that Regan is moving on with Aldo, who challenges his influence over her.

Aldo's father and a dedicated restaurant owner, Masso is deeply rooted in his Italian heritage and offers a warm yet cautious presence, especially in regard to Aldo's relationship with Regan.

Regan's successful sister, who is often seen as the favored child by their parents, building a contrast against Regan's struggles in both personal and familial contexts.

Regan's critical and distant parents, whose treatment and expectations of Regan contribute to her emotional struggles and drive her to seek affirmation elsewhere.

Regan's niece and one of her favorite family members, who provides some familial connection amidst Regan’s troubled relationship with her own parents.

Regan’s court-appointed psychiatrist, who primarily focuses on maintaining Regan’s medication regimen and fails to engage with her artistic progress.