The CEO of the Eldridge Institute and the main antagonist, depicted as a brilliant but ruthless figure whose invention of interdimensional travel serves his self-serving ambitions.

Cara’s handler at the Eldridge Institute, who initially keeps a professional distance but gradually reveals a more compassionate side and becomes a key ally and love interest.

The emperor of Ashtown and Adam Bosch’s brother, whose character differs greatly across worlds, showcasing both a violent ruler and a more peace-oriented leader.

A senior traverser and mentor to Cara at the Eldridge Institute, offering her guidance born from his own experiences of overcoming hardship.

Cara’s younger stepsister and a devout leader within the Rurals, embodying unconditional love and moral guidance in Cara’s life.

Cara’s doppelgänger from Earth 175, portrayed as a hardened survivor willing to betray others to escape her world’s harsh conditions.

The owner of the House in Ashtown, known for providing sanctuary and wielding ambiguous yet significant power and influence.

Initially appearing as a minor antagonist extorting money from Cara, but later revealed as a principled man deeply loyal to Nik Nik.

Cara’s mother whose life across worlds is marked by addiction and abuse, leading to strained relationships with Cara’s counterparts.

Esther’s twin brother and Cara’s stepbrother, who rebels against the Rurals' piety and seeks identity and power as a runner in Ashtown.

Cara’s stepfather and the spiritual leader of the Rurals, a man of kindness and integrity who accepts Cara unconditionally.