"There was Antonin Dolohov. ...I - I saw him torture countless Muggles and - and non-supporters of the Dark Lord."
-- Igor Karkaroff giving testimony in Dumbledore's Pensieve memory (GF30)
Antonin Dolohov was one of Tom Riddle’s friends after leaving school, one of the original Death Eaters (HBP20).
He was sent to Azkaban for the murders of Gideon and Fabian Prewett (OP25). Dolohov escaped from Azkaban early in 1996, along with Bellatrix Lestrange and several other high-security prisoners, and rejoined Voldemort. He participated in the Battle of the Department of Mysteries and was recaptured. Dolohov's "specialty attack" was a jet of purple light cast in a zigzag pattern which causes severe internal injury (OP31). He used this on Hermione. Dolohov was also the one to use "Tarantallegra" (Dancing Feet Spell) on Neville, which caused the prophecy to break when Neville's dancing leg kicked it (OP35).
Released again from Azkaban, Dolohov attacked Harry, Ron, and Hermione in a café on Tottenham Court Road with Rowle (DH9). During the Battle of Hogwarts, Dolohov killed Remus Lupin (DH31, BLC). On Pottermore, Rowling says that "Remus Lupin met his end at then hands of Antonin Dolohov, one of the longest-serving, most devoted and sadistic of all Voldemort's Death Eaters." Dolohov was also on the lookout for Harry with Yaxley in the Forbidden Forest, having to report to Voldemort that Harry hadn't come (DH34). Dolohov was finally taken down by Flitwick (DH36). However, because he "fell at Flitwick's hands" it's not 100% certain he was killed by Flitwick at the time.
Dolohov's "specialty attack" was a jet of purple light cast in a zigzag pattern which causes severe internal injury (OP31). He enjoyed torturing "countless Muggles" and "non-supporters of the Dark Lord" (GF30).
Possibly named for a character in the Russian novel War and Peace by Tolstoy.