| Larson | Creacher | The island caretaker in 2003. The suspect on the 2003 killing spree. |
| Ronan | Delaney | Seth's father. The island owner. |
| Seth | Delaney | Jo's boyfriend. |
| Alain | Dunne | The former student at Rock House School. |
| Christopher | Jackson | Porter's alleged son. |
| Porter | Jackson | The island's local resident. The boatman. |
| DS | Johnson | The detective in charge in Creacher murders. |
| Bea | Leger | Hana and Jo's older sister. |
| Hana | Leger | Jo's sister. One of the island visitors. |
| Jo | Leger | Hana's sister. One of the island visitors. |
| Farrah | Riley | Will's younger sister. The Lumen manager. |
| Will | Riley | Elin's boyfriend. The founder of LUMEN. |
| Rob | Tooley | The missing guest. |
| Lois | Wade | Missing. |
| Elin | Warner | A former agent of crime investigation unit. A detective sergeant. |
| Isaac | Warner | Elin's brother. |
| Michael | Zimmerman | The cleaner of the pavilion. |
| Anna | | The HR. Elin's boss. |
| Caleb | | Bea's boyfriend. |
| David | | Will's friend. |
| Della | | Bea's assistant. |
| Edd | | Jo's driver. |
| Hayler | | Murderer of Elin's brother's fiancé. |
| Jared | | The Lumen's supervisor. |
| Jon | | The medic. |
| Josh | | Will's friend. |
| Justin | | The Lumen's security guy. |
| Leon | | A CSI agent. Elin's colleague. |
| Liam | | Hana's dead boyfriend. |
| Maya | | Hana and Jo's cousin. |
| Mieke | | One of the forensic pathologists. |
| Ollie | | Thea's friend. |
| Rachel | | Leon's partner. |
| Sam | | Elin's sister. Deceased. |
| Sofia | | Maya's younger sister. |
| Sol | | Maya's ex. |
| Steed | | A detective constable. Elin's colleague. |
| Thea | | Murdered. |
| Tobias | | Farrah's ex-boyfriend. |
| Tom | | The water sports instructor. |
