Effy is an architecture student at a prestigious college in Llyr. As the only female student in her program, she faces constant institutional sexism and social isolation. She relies heavily on literature, taking comfort in Emrys Myrddin's stories to manage her anxiety and childhood trauma. Following a traumatic encounter with her academic advisor, she travels to the rural south to take on the Hiraeth Manor project as both a career opportunity and an escape.

Preston is an Argantian literature student seeking to complete his thesis on Emrys Myrddin. He relies on pragmatic logic and values objective truth over local superstition. His dedication to uncovering facts creates tension with Llyrian traditions. Prejudice against his mixed heritage presents significant academic hurdles, forcing him to be a meticulous and guarded researcher.

Ianto is the son of Emrys Myrddin and the custodian of the decaying Hiraeth Manor. He oversees Effy's architectural project while fiercely protecting his father's legacy. He exhibits an unpredictable personality that oscillates between warm hospitality and erratic intensity. He struggles with the physical and mythological burdens of his property. The Fairy King, a legendary figure from local lore who haunts Effy's nightmares, represents the dark supernatural influence surrounding the estate.

The daughter of the wealthy poet Colin Blackmar and a figure deeply connected to Emrys Myrddin's early career. She shares her name with the famous protagonist of Myrddin's epic novel. Her historical letters and photographs serve as a crucial puzzle piece for Preston and Effy as they investigate the origins of the celebrated Llyrian text.

An architecture professor at Effy's university who wields considerable power over her academic progress. He acts inappropriately toward female students, creating a hostile environment. His actions cast a long shadow over Effy's mental health and reflect the broader institutional prejudice present at the college.

A deceased Llyrian author celebrated as a national hero and preserved as one of the seven Sleepers meant to magically protect the country. His famous work forms the foundation of Llyrian cultural identity. Despite his death, his historical actions, personal letters, and private journals drive the ongoing conflict between Effy and Preston.

An elderly, wealthy poet who resides in a luxurious home that contrasts sharply with the decay of Hiraeth Manor. He is deeply entrenched in the literary history of Llyr and holds valuable information regarding Emrys Myrddin's early career. He carefully guards his family's secrets and prefers to maintain control over social situations.

An editor associated with Colin Blackmar and the late Emrys Myrddin. He uses his inside knowledge as leverage in social situations and acts unprofessionally when approached for information by students.

Effy's roommate at the university who studies at the nearby music college. She is observant and practical, offering a grounded perspective to counter Effy's anxious nature.

A barrister employed by Ianto Myrddin. He is practical and dismissive of southern superstitions. He serves as a reluctant guide between the modern town of Saltney and the isolated, decaying estate.

An academic advisor at the literature college who oversees Preston's studies. He represents the traditional, male-dominated hierarchy of the university system and actively shapes the academic narrative.

The head of the literature college. He is a prominent figure in the academic establishment who attempts to maintain the status quo and control the publication of new, controversial research.

A cold and distant woman whose dismissive cruelty affects her daughter's self-esteem. Her decision to abandon Effy near a river during childhood caused lasting trauma that manifests in Effy's ongoing fears.