It's possible that Antonin Dolohov attended Hogwarts at the same time as Tom Riddle, Jr., and may have been a member of the Slytherin house as well as a member of Tom Riddle's gang.
First Wizarding WarEdit
Antonin Dolohov was one of the early followers of Rom Riddle and served him even before his master began open hostilities against the rest of the wizarding world. He was among the Death Eaters who travelled to Hogsmeade, along with Nott, Rosier, and Mulciber, when Voldemort attempted to take the position of Defense Against the Dark Arts Professor at Hogwarts, ostensibly to "wish him luck".
According to Igor Karkaroff, Dolohov tortured many Muggles and non-supporters of Lord Voldemort during the First Wizarding War. With the help of four other Death Eaters, he murdered Fabian and Gideon Prewett, the brothers of Molly Weasley. He was not the only participant in the act, though, since Alastor Moody informed Harry Potter years later that it took five Death Eaters to kill the two wizards, whose murders were described as "brutal".
After the downfall of Voldemort in 1981, Dolohov was captured and sent to Azkaban prison for his crimes. He was the first name Death Eater Igor Karkaroff turned over to the Council of Magical Law in an attempt to get himself freed from Azkaban, only to be informed that Dolohov had been captured around the same time as him.
Second Wizarding WarEdit
Early in 1996, Dolohov, along with the Lestranges and several other Death Eater convicts, escaped Azkaban and rejoined Voldemort. It was speculated in the Daily Prophet that the escape was aided by Sirius Black, but that was refuted in the aftermath of the Battle of the Department of Mysteries.
Battle of the Department of MysteriesEdit
On June 17, 1996, Lord Voldemort lured Harry Potter to the Ministry of Magic precipitating the Battle of the Department of Mysteries. During the battle, Dolohov was paired with Jugson as the Death Eaters searched for the five students who had come to the Ministry with Harry Potter. They tracked Harry Potter, Hermione Granger, and Neville Longbottom to a room off the Time Chamber, hitting the three of them with Impediment Jinxes. When Dolohov began to alert the other Death Eaters as to their location, Hermione silenced him to prevent it. He retaliated with an unnamed curse which, despite being weaker than normal, because it was cast non-verbally, severely injured Hermione. With a kick, Dolohov broke Neville's wand and nose and then cornered Harry, wordlessly threatening him. However, he was momentarily distracted, giving Harry the chance to body-bind him.
Before several Order of the Phoenix members arrived, Dolohov recovered and he was able to defeat Alastor Moody in a duel. He then attacked Harry with the same spell he used on Hermione, but most of the harm was blocked by Harry's shield charm. He tried to use it again when duelling with Sirius Black, but was incapacitated by Harry before he could follow through.
Presumably, Dolohov was captured in the aftermath of the battle by Aurors and returned to Azkaban.
Death Eater PlansEdit
By the summer of 1997, Dolohov was again at large following another Azkaban break-out. He attended the Death Eater meeting at Malfoy Manor that summer and was seated by Yaxley; he was impressed when Yaxley announced that he had placed Pius Thicknesse, the head of the Department of Magical Law Enforcement, under the Imperius Curse. He, along with other Death Eaters, laughed when Voldemort insulted Bellatrix Lestrange and the Malfoy family
Luchino Caffe DuelEdit
Shortly after the Death Eaters took over the Ministry of Magic and placed the Taboo curse on Voldemort's name, Dolohov and Thorfinn Rowle tracked Harry Potter, Hermione Granger, and Ron Weasley to a cafe on Tottenham Court Road. During the skirmish that ensued, Dolohov bound Ron with conjured ropes and slammed an invisible Harry into a wall with Expulso, but just before Harry dropped his wand, Hermione hit Dolohov with a Full Body-Bind Curse. Dolohov and Rowle's memories were then modified by Hermione shortly after.
This spell seemed to work well enough at the time, but it actually had not been very effective, as the three friends found out later when Harry had a vision of Lord Voldemort torturing Rowle; it is implied that Rowle at least, and perhaps both of them, were being punished for their failure by being subjected to the Cruciatus Curse. Dolohov may have been among the Death Eaters assigned to keep an eye out for 12 Grimmauld Place, former headquarters of the Order of the Phoenix and temporarily hide-out for Harry, Ron, and Hermione, as one of the Death Eaters mentioned watching the gap between houses 11 and 13 on the first of September was "the man with the twisted face", a characteristic often used to identify Dolohov. The Death Eaters were able to find out Harry, Ron, and Hermione's location because Lord Voldemort's name was Tabooed.
Battle of HogwartsEdit
During the Battle of Hogwarts on May 2, 1998, Dolohov was seen fighting against Dean Thomas and Parvati Patil; Parvati shot a Full Body-Bind Curse at him in defense of Dean. Dolohov also killed Remus Lupin in a duel. The nature of Remus's death was not revealed, but his body was peaceful-looking, suggesting that Dolohov used the Killing Curse of his own curse, as neither leaves visible marks. After Voldemort called a retreat and gave Harry Potter one hour to turn himself over, Dolohov and Yaxley stood guard in the Forbidden Forest. Harry followed them to the Death Eater camp to confront Voldemort. When the battle later resumed, Dolohov was defeated by Filius Flitwick, a former duelling champion. His fate beyond this is unknown.