Father of Carobelle and Theodore Nott. A widower, formerly married to the now deceased Imogen Nott.
Mr. Nott became a Death Eater in 1955 (one of the very first), and fought in the First Wizarding War. He may have attended Hogwarts with Tom Riddle. He did not search for Voldemort after his downfall, but does apparate to his side after his return in 1995, professing to be his most faithful servant. In 1996 he is injured by Harry/Hermione in Battle of the Department of Mysteries and left behind by the Death Eaters, and sent to Azkaban. In 1997 he escaped and rejoined Voldemort. He is presumably killed or re-imprisoned after Voldemort’s death.
Barnaby Nott is the father of Carobelle Nott and Theodore Nott. His much younger wife (Imogen) died when the children were young. She was pure blooded and a perfect social hostess. He regrets that she died, but feels that she lived long enough to fulfil her primary function and give him a pure-blooded heir.
Barnaby works in the Department, in a role related to International Wizarding relations, and frequently travels abroad.
He is a serious and ambitious man, and expects his children to comport themselves in accordance with his ambitions for them. Most of his goals center on Theodore, as his son and heir.
He has made it clear to Carobelle that her function is to make a politically advantageous match to a pure-blooded young man, so they can have pure-blooded children and keep the pure-blooded line alive.
He was suspicious that his wife’s death was a magical attack, perhaps from those who suspected (rightly) that he sided with Voldemort in the first wizarding war, or, even more likely, from one of his former comrades who was bitter that Nott escaped accusation and punishment, while others were sent to Azkhaban. Afraid for his children (and believing that the preservation of the pure blood line trumps all other considerations), he hid them in gender-segragated muggle boarding schools.
He took pains to assure that they had enough background about the wizarding world to not be socially disadvantaged by this time in the muggle world, but never considered the possibility that his daughter would like it, or get the insane idea to apply to muggle ballet academy. She is going to Hogwart’s and that is the end of the discussion.
Learning from this experience, he transferred Theodore out of the muggle boarding school and into a Wizarding prep school for his last year prior to attending Hogwarts. (He will attend in Harry Potter’s year.) Enough years had elapsed since the wizarding war that Barnaby felt there was little risk.
Barnaby has recently begun a flirtation with Josephine nee Yaxley Pomme, Cordelia’s mother. Her bloodline is pure, and it really has become tiresome to not have a social hostess at his beck and call for his professional socializing.
[Note that Barnaby will be publicly known to be a death eater as of the school year beginning in fall 1996, while Carobelle and Theodore are still at Hogwarts. Professor Slughorn passes Theodore over for the Slug Club because of his father’s reputation.]