A 22-year-old native of Togliatti, Russia, Demagin played in Belarus this past season for Dynamo Minsk. In 46 games, the 6-0, 174-pounder notched 16 goals and added 15 assists for 31 points. That was good for second on the team in goals and tied Demagin for third on the club in points. In 114 career games for Dynamo Minsk in the top Belarussian league over four seasons, Demagin posted totals of 18 goals and 22 assists for 40 points, plus 46 penalty minutes.

Demagin led the Belarussian Second Division in points and assists in 2005-06 for Dynamo Minsk 2, striking for 29 goals and 32 assists for 61 points in only 39 games. He also topped Dynamo Minsk 2 in points in 2004-05, and tallied the second-most goals and assists on the club, with a slate of 27-26-53 in 36 games.

Internationally, Demagin skated for Belarus at the 2007 World Championships, in which he suited up for three games and registered two penalty minutes. Demagin also helped represent Belarus in the 2006 World Junior Championship, notching two goals and an assist for three points in five appearances.