Crystal Reed as Abigail "Abby" Arcane: A CDC doctor investigating a horrific life-threatening epidemic in her hometown while facing her past again.[1] Melissa Collazo portrays teenage Abby. Virginia Madsen as Maria Sunderland: The wife of Avery Sunderland, whose grief over the loss of her daughter, Shawna, resurfaces when Abby returns home, and draws Maria into the supernatural mysteries of the swamp.[2] Andy Bean as Alec Holland: A disgraced biologist working for Avery. Murdered when he starts to uncover an illegal operation in the swamp, his memories survive inside of Swamp Thing.[3] Derek Mears as Swamp Thing: A plant-based entity created from the memories of Alec Holland.