Robin is a Cantonese youth taken from his homeland to England by Professor Lovell. Plucked from poverty after an epidemic takes his family, he receives a strict classical education to prepare for the Royal Institute of Translators. He has white-passing features that shield him from overt street harassment, though he feels deeply isolated by his unique position. He studies diligently, eager to earn a place in academia and secure a safe future.

Griffin is a former student of the Babel Institute who bears a striking physical resemblance to Robin. He left Oxford after struggling to retain enough of his native language to properly conduct translation magic. Now living on the fringes of society, he works against the institution that trained him. He views the British Empire with profound cynicism and believes radical action is necessary.

Ramy is a charismatic scholar from Calcutta and a member of Robin's translation cohort. Coming from a family that lost its wealth under British rule, he learned early to manage white society by playfully leaning into English assumptions to disarm prejudice. Despite his confident exterior, he harbors deep resentment toward colonial forces.

Letty is the daughter of a British admiral who attends Oxford against her father's wishes. Endowed with a natural gift for languages, she acquired her education by secretly listening to her brother's tutors. As a woman, she faces intense sexism that excludes her from campus housing. Her privileged background makes her largely blind to the racial discrimination experienced by her friends.

Victoire is a talented scholar with roots in both France and Haiti. Raised as a domestic worker before securing her place at Oxford, she deals with the overlapping oppressions of being a Black woman in 1830s England. She is a highly resourceful and intellectually gifted student. Because of the university's exclusionary housing rules for women, she lives off-campus with Letty.

Richard Lovell is an elite translator, Oxford professor, and an architect of the British Empire. He is a strict, frequently abusive guardian who uses physical discipline to control his wards. He views translation as a crucial tool for maintaining British imperial dominance, expecting absolute obedience from those under his roof.

Anthony is a Black upperclassman at Babel who acts as a guide to the new students. Originally an enslaved boy from Barbados, he gained his freedom when Babel purchased him for his linguistic talents. He possesses a calm demeanor and manages to operate successfully within Oxford's elite, racially hostile environment. He serves as an early mentor figure for Robin's cohort.

Jerome Playfair is the headmaster of the Babel Institute. He maintains a genial, academic exterior and speaks in elevated, idealistic terms about the power of translation to connect cultures. Despite this benevolent presentation, he is deeply committed to the British Empire and firmly controls the operations and security within the tower.

Professor Chakravarti is one of the few faculty members at Oxford from a colonized culture. He conducts tutorials with Robin, using these sessions to study the mechanics of the Chinese language. He takes an academic approach to his work, extracting linguistic knowledge from native speakers to fuel Babel's translation magic.

Professor Craft is the sole female faculty member at Oxford. Despite her unique position in a male-dominated institution, she maintains a strict professional distance. She explicitly rebuffs Letty's attempts to bond over their shared gender-based struggles, preferring to focus entirely on her academic work.

Sterling is a highly successful translator and a proud graduate of Babel. He wholeheartedly embraces British imperialism and utilizes translation to ensure his country's material prosperity. He works directly as an agent of the empire, carrying out unsavory tasks required to maintain global dominance.

Abel Goodfellow is a strong, working-class Englishman who resents the economic damage caused by the silver industrial revolution. He is a practical organizer who understands the dynamics of street-level protest and class solidarity. He views the academic work at Babel with deep suspicion regarding its impact on everyday laborers.

Ibrahim is a scholar of color at Babel who recognizes the importance of historical archives. He values documentation and takes on the responsibility of recording events from the perspective of marginalized students. He is acutely aware of how the empire erases histories that do not serve its interests.

Juliana is a student at the Babel Institute from a colonized background. She experiences the same intense academic pressures as her peers while dealing with the prejudices of the university. She quietly observes the growing tensions between the students and the administration.

Meghana is a student of color at the university. She faces rigorous demands to prove her worth in an institution designed for white British men. She forms part of the small network of diverse students trying to survive at Oxford.

Yusuf is a law student of color at Oxford. His legal training provides him with a practical framework for understanding the rules of the empire. He uses his knowledge of treaties and agreements to support his fellow marginalized peers.

Mrs. Piper is the housekeeper at Richard Lovell's London home. She maintains the domestic order but turns a blind eye to the physical violence Lovell inflicts on young Robin. She represents the complicity of ordinary citizens in imperial cruelty.

Eveline is a historically significant former Babel student who studied alongside Sterling, Anthony, and Griffin. Despite having a dedicated desk preserved in Professor Playfair's classroom, she mysteriously vanished from official records. Her legacy as a brilliant silversmith looms large over the younger scholars.

Commissioner Lin Zexu is an imperial official in Canton, China. He is a scrupulous leader dedicated to halting the British importation of opium into his country. He prioritizes the health of his people over the financial demands of the British Empire, leading to tense trade negotiations.

Mr. Baylis is the liaison for a trading company managing operations in Canton. He is openly racist and condescending toward Chinese officials, fiercely advocating for unchecked trade. Driven by greed, he operates with intense prejudice and imperialist entitlement regarding the smuggling of opium.

Horace Wilson is the secretary of an Eastern languages organization in Calcutta. He sponsors Ramy's education in England after recognizing the boy's quick intellect. He treats his Indian employees with distinct condescension, seeing them as resources rather than equals.