Arthur is described by Jordan Kennedy as "a short man with a constant scowl, thinning white hair, and a well-chewed cigar," as well as looking like "his denim shirt had once contained quite an athletic build, but it had long since sailed" (MAG 55).
Sometime in 2006, Arthur sends Eugene Vanderstock to tell Gertrude that Agnes is dead, and to threaten her (MAG 139). Sometime after that, Arthur is removed as the leader of the Cult of the Lightless Flame and finds a nest of The Corruption in a house, which he then purchases, with the intent to destroy it when the time is right (MAG 145).
In 2009, Arthur meets with Gertrude at the Magnus Institute, hoping to use her to restore his standing with the Cult of the Lightless Flame, which has weakened in favor of Diego Molina in the wake of Agnes' death. He learns that Gertrude has done something to Eugene Vanderstock which seems to frighten him (MAG 145).
Gertrude and Arthur discuss Agnes's life and death. They also discuss how The Web bound Gertrude and Agnes' lives together using the ritual Gertrude performed attempting to prevent Agnes and the Cult from performing their own ritual. Gertrude sends Arthur away with a warning to the remaining Cult members not to make a move against her (MAG 145).
In 2014, one of Arthur's tenants, Jane Prentiss, is found with her arm buried in what appears to be a wasp's nest and is taken away to the hospital. Arthur calls Jordan Kennedy to remove the nest wasp's nest. When Jordan is unable to remove the nest, Arthur is forced to set himself alight to burn the house down and destroy the nest (MAG 55).
Bold marks episodes where Arthur has given a statement.