Tristian is the leader of Unit Seven, and his unwavering faith in his team makes him a beacon of hope, community, and optimism in this bleak, postapocalyptic world. Whereas Sasha tries to remain isolated, Tristian relentlessly pursues her as a vital addition to his team, and he looks for a basic humanity in all of his recruits. Having been the recipient of her empathy and medical skill, he recognizes Sasha’s wasted potential and makes her a medic in his unit. Unlike other commanders, he fosters a powerful sense of family within his team, creating a tight-knit community and challenging Sasha’s belief that survival is a solitary endeavor.

Tristian’s leadership is defined by fierce loyalty, and he’s deeply protective of his unit. This instinct is a direct result of past betrayals, specifically Lyssa Burdon’s coup, which destroyed his original unit, the Angels. To protect his new team from Haven’s cruel health-score system, he arranges for Sasha to secretly treat them when they’re injured, and he consistently shields his unit from outside threats both within and beyond Haven. This protective drive extends to Sasha personally, as he defends her from institutional persecution and personal attacks.

While idealistic, Tristian is not ignorant of the political corruption in Haven and is willing to bend the rules to counter unjust laws and commands. His complex history with Commander Burdon emphasizes his refusal to compromise his integrity for the sake of seizing power. As he and Sasha gradually develop a romantic connection, he works to break down her resistance and fear, knowing that her addition to the team can only benefit Unit Seven’s actions on behalf of Haven’s future.

Levi was Tristian’s partner for many years but volunteers to become Sasha’s partner, serving as a mentor for her. Initially, he’s a man of few words, and he refuses to coddle Sasha’s sullen resistance to learning the skills she needs, instead demanding that she confront her psychological barriers and try her hardest at every challenge. He pushes her to her physical and emotional limits, believing that people must be fully committed to their unit and to their own survival.

Beneath his reserved, demanding exterior, Levi possesses a strong empathy born from his own traumatic past. A former foster child with a deep-seated anger, he finds a kindred spirit in Sasha and shares his own past struggles, telling her that she’s experiencing “grief for all that was and all that will never be” (199). This moment of vulnerability establishes a crucial bond built on mutual understanding. His loyalty to Tristian and the unit is absolute, and he staunchly defends Sasha as she adjusts to her new position. He gives her the call sign “Phoenix,” which honors her resilience and her capacity to rise from the ashes of her past.

Kaleo is the commander of Unit Five and is initially portrayed as an antagonist and rival to Tristian. His arrogance, ambition, and aggressive demeanor arouse Sasha’s ire, and she falls in line with Unit Seven’s collective dislike of him. He takes an uncompromising, win-at-all-costs approach to his missions. Ostensibly aligned with Commander Burdon, he actively antagonizes Unit Seven throughout most of the novel, but he eventually reveals himself to be a more complex anti-hero. His relationship with Rumi and his secret collaboration with Dr. Kumar show that he’s playing a long game and attempting to expose Burdon’s corruption. His motivations are ultimately geared toward saving Haven, but his methods are deceptive and put him in direct conflict with Tristian.

As the primary antagonist and the formidable Commander of the Force, Burdon embodies the corrupting influence of power and The Human Tendency to Perpetuate Oppression. Motivated by sheer ambition, she has a bitter and complex history with Tristian, whom she sees as a rival. After seizing control of the Force through a coup that dismantled Tristian’s original unit, the Angels, she rules the Force (and Haven) with paranoia and vindictiveness. Burdon consistently works to undermine Unit Seven, viewing their loyalty to Tristian as a threat to her authority. Her tactics are cruel and manipulative, particularly when she treats the mission to save Haven as a political game, using her power to settle personal scores.

Dr. Kumar, a mentor from Sasha’s time in the Ward, is one of the few people who sees beyond her hardened façade, recognizing her deep-seated compassion and medical talent. He gives her the nickname of “Death’s Angel” because he admires her ability to hold vigil with dying patients and put herself at risk to save lives. Kumar engages in a quiet but firm rebellion against the cruelty of Haven’s health-score system, secretly enabling Sasha’s efforts to help others. He also plays a pivotal role by entrusting Sasha with the key to the hidden supply cache.

Ingrid is a key member of Unit Seven who initially acts as an antagonist toward Sasha. Her hostility is rooted in her unresolved grief over the death of her partner, Lily, and she unfairly blames Sasha for failing to save Lily’s life. She sees Sasha as a painful reminder of her loss, but she eventually learns to accept Sasha as a member of the team. The two reconcile when Ingrid relies on Sasha to save her sister, Bretta, from the illness spreading through Haven.

Damien functions as Unit Seven’s comic relief, using a constant stream of jokes and banter to lighten the grim reality of their existence. However, his jovial exterior conceals the pain of a chronic ankle injury that he sustained when his own family abandoned him during the war. He’s one of the first members to welcome Sasha, and his loyalty proves unwavering. His boyfriend, Noah Henderson, is a member of a different unit and is eventually revealed to be a spy who is loyal to Force Commander Burdon.

Isla, the optimist of Unit Seven, is kind-hearted and makes a genuine effort to befriend Sasha from the moment she joins. However, her cheerful demeanor masks her own inner turmoil over her complicated romantic history with both Patrick and Levi.

Patrick is Unit Seven’s logical and methodical strategist and is often concerned with rules and protocol. His devout Catholic faith, symbolized by the cross he constantly wears, represents his struggle to reconcile his sense of morality with the violent necessities of their world. As Rumi’s steadfast and loyal partner, he’s devastated by her choices at the end of the novel.

Rumi is the quiet observer of Unit Seven. Her silence is often mistaken for aloofness, but she’s exceptionally perceptive, noting everything that happens and making shrewd deductions about people’s personalities. While she is deeply loyal to Unit Seven, she also engages in a secret relationship with Kaleo and operates in a morally gray area, utilizing deception and espionage in order to safeguard her loved ones and protect Haven.