Second half of 1981 (before 17 November)
Robbie Fenwick (possibly)
Order of the Phoenix
Though nothing is known about his early life, it is likely that as a British wizard, he attended Hogwarts School of Witchcraft and Wizardry when he turned eleven and that he had graduated prior to 1981 as the First Wizarding War ended that year.
First Wizarding War
During the First Wizarding War, Benjy became member of the Order of the Phoenix, an organisation led and founded by Albus Dumbledore, in order to oppose the evil Lord Voldemort and his Death Eaters. Benjy most likely fought in several battles of the First Wizarding War.
Benjy was brutally killed by Rupert Wilkes during the war, who fired a curse that blasted Benjy to pieces, and then disposed of his remains. According to fellow Order member Alastor Moody, the Order, in their search for Benjy's body, only ever found "bits of him."