Arthur is a theoretical physicist and astronomer who was in love with Elizabeth "Liz" Pennykettle when they were both younger. However, Arthur was unaware at that time of Liz's special relationship to the dragons and Guinevere, and when he hears about Liz's "pregnancy" with Lucy from "Aunty Gwyneth", he believes there is another man involved and leaves. We discover him many years later, in the book Fire Star, now under the name of Brother Vincent and sheltering in a monastery on Farlowe Island. In the Fire Ascending Arther very little is said about him. He is beside Liz when she dies.