Sebastian Henry Longbottom (b. Jun 13, 1979) is the Half-Blood member of the noble Longbottom Family. He is the younger twin brother of Bartholomew Longbottom, son of the late Elijah Longbottom, his muggle wife Monique Longbottom, and the first cousin of Neville Longbottom. He currently attends Hogwarts School of Witchcraft and Wizardry and is a member of Slytherin House.
Sebastian and his brother Barry were born on June 13, 1979, in France. At the time, Voldemort's reign of terror was encompassing nearly all of Europe and Asia, and the Longbottoms--like many noble families--separated to keep him from exterminating the entire line. This proved ineffective when He found and murdered Elijah and Monique Longbottom while they were at a restaurant in Wizarding Paris. The two children, now orphans, were taken in by their grandparents, Augusta Longbottom and Harfang Longbottom and were moved into the ancestral home of the Longbottom family for security, Lakeview Hall.