Dinanath "Deen" Dutta is an Indian rare books dealer of Bangladeshi descent living in New York. While visiting Kolkata, he learns of a folk legend about the Gun Merchant that captures his attention. He operates as a cautious observer, approaching the mysteries surrounding the shrine with a mix of academic curiosity and mild skepticism.

Giacinta "Cinta" Schiavon is a highly esteemed Italian historian and professor specializing in Venetian history. Following the tragic deaths of her husband and daughter, she relocated to the United States and befriended Deen. She approaches historical events with a deep respect for the supernatural, believing that stories hold active power in the present day.

Tipu is a restless youth from the Sunderbans who makes his living helping migrants illegally cross borders via the internet. Raised partly by Piya after his father's death, he rejects formal education and conventional authority due to his experiences with caste-based discrimination. After an encounter at the Gun Merchant's shrine, he begins experiencing intense physical and mental symptoms.

Rafi is a young Muslim boy and the grandson of the caretaker of the Gun Merchant's shrine. He possesses deep knowledge of the local legends and the specific symbols adorning the temple walls. He functions as a steady, protective companion to Tipu.

Piyali "Piya" Roy is an Indian American cetologist who teaches marine biology in Oregon but frequently visits Kolkata for research. She studies Irrawaddy river dolphins and maintains a strictly scientific, rational perspective on the world. She acts as a foster parent to Tipu and feels a deep sense of responsibility for his family's welfare.

Nilima Bose is a wealthy, influential woman and Deen's distant aunt. Decades earlier, she discovered the shrine of the Gun Merchant while distributing relief supplies after a devastating cyclone. Her persistent interest in preserving the shrine's history initiates Deen's involvement in the mystery.

Moyna is Tipu's mother, living in the Sunderbans. Widowed after her husband Fokir died during a cyclone, she worries constantly about her son's erratic behavior and his mysterious, internet-based employment.

Horen Naskar is a seasoned fisherman from the Sunderbans who originally accompanied Nilima when she first discovered the shrine in 1970. He possesses his own version of the Gun Merchant's folklore, passed down through generations of river workers.

Kanai Dutt is Deen's distant relative. He serves as a catalyst by introducing Deen to the local folklore and providing him with the initial contacts needed to explore the Sunderbans.

Gisa is Cinta's niece who works on documentary films. She shares her aunt's sensitivity to the unseen, claiming to feel the presence of her deceased cousin Lucia. She plans to shoot a documentary about the immigration crisis in Italy.

Lucia is Cinta's deceased daughter. Though she is physically absent, her memory profoundly shapes Cinta's life, and Cinta frequently senses her presence or hears her voice during moments of crisis.

Lubna-khala is a Bangladeshi woman who has lived in Venice for two decades. Having survived a devastating cyclone in her youth, she now works to assist newly arrived migrants in building their lives in Italy.

Bilal is Rafi's housemate in Venice and a fellow migrant. Having experienced the arduous journey from Bangladesh to Europe by sea, he understands the deep bonds formed between traveling companions and worries about Rafi's debts.

Palash is a Bangladeshi migrant who originally came to Italy as a student but dropped out and lost his work permit. He now works alongside Lubna-khala to raise money and support for incoming refugees.

Munir is Lubna-khala's deceased husband. He was an activist working for migrants and died under mysterious circumstances while investigating captive refugees in Sicily.

Fokir is Tipu's deceased father, a villager from the Sunderbans who died protecting Piya during a violent cyclone years earlier. His death leaves a lasting impact on his family and motivates Piya's ongoing support for them.

Durga is Deen's deceased first love. Her tragic death years ago prompted Deen to leave India for the United States, and her memory continues to cast a shadow over his romantic life.

Rani is the oldest member of a pod of Irrawaddy river dolphins that Piya studies in the Sunderbans. Fitted with a GPS tracker, her unusual beaching behavior becomes a source of scientific and supernatural debate among the human characters.

The Gun Merchant (Bonduki Sadagar) is a legendary figure who fled overseas to escape the wrath of Manasa Devi, the goddess of snakes. His mythological journey across the world parallels the modern-day travels and tribulations of the central characters.

Manasa Devi is the Hindu goddess of snakes and venomous creatures. In legend, she pursues those who refuse to acknowledge the power of the natural world, acting as a divine intermediary between humans and nature.

Ilyas is a historical and legendary ship captain who buys the Gun Merchant out of slavery and becomes his trusted traveling companion. Historical clues suggest he may have been a Portuguese Jew.