Brother Doorkeeper
A member of the Elucidated Brethren of the Ebon Night, Brother Doorkeeper was responsible for admitting other members to their secret-society meetings and confirming they knew the right passwords. Lots of passwords. Not very original passwords either; at least, they failed to keep a fellow who was looking for a different secret society's get-together from unwittingly crashing their first meeting in Guards! Guards!. His duties as door-warden would have been easier if the passwords' composer had shown more originality, or at least if the dread portal hadn't jammed so easily.
Worked for a Mr. Critchley at the Bakers' Guild, whom he felt oppressed him terribly by shouting at him. Also "oppressed" by a woman at the vegetable shop, whose establishment was among the first targets of the Ankh-Morpork dragon's fiery breath. Brother Doorkeeper was pleased by this venal retribution, but may have had second thoughts in the instant or so it took for him to burn to ashes, a few nights later.
Possibly the tallest of the Brethren, as Brother Watchtower briefly mistakes Death for Brother Doorkeeper after their mutual incineration.