Thin Lucy was a resident of Glyngatwg who frequented the Y Pren Marw inn with Ifor Jones.
In an alternate timeline, in 2024, she was at the inn when Ruby Sunday arrived saying the Fifteenth Doctor had disappeared and a woman was stalking Ruby at 73 yards away. Thin watched as fellow resident Joshua Steele attempted to talk to the woman only to run away screaming.
Soon after, when Ruby mentioned the Doctor had broken the fairy circle on the clifftops, Thin listened as Ifor and the other pub goers teased Ruby about a folk's tale about the murderer "Mad Jack", before bursting out laughing at Ruby believing them. (TV: 73 Yards [+]Russell T Davies, Doctor Who series 14 (BBC One and Disney+, 2024).)