i Register
In some senses, doorkeeper is marked as figuratively. Watch for register when choosing this word.
noun
The person in charge of an entryway, sometimes responsible for security in the immediate area around the entryway.
Near-synonyms: doorman, concierge, bouncer
The manager at Carnegie Hall was told to get another usher in his stead; the doorkeeper at the theatre was warned not to admit him to the house; and Charley Edwards remorsefully promised the boy's father not to see him again.
Someone with power to keep others out of some sphere or activity.