 First Sergeant Martin Christopher Keamy is a fictional character played by Kevin Durand in the fourth season and sixth season of the American ABC television series Lost . Keamy is introduced in the fifth episode of the fourth season as a crew member aboard the freighter called the Kahana that is offshore the island where most of Lost takes place . In the second half of the season , Keamy served as the primary antagonist . He is the leader of a mercenary team hired by billionaire Charles Widmore ( played by Alan Dale ) that is sent to the island on a mission to capture Widmore 's enemy Ben Linus ( Michael Emerson ) from his home , then torch the island . 
 First Sergeant Martin Christopher Keamy <a href='drop_aux' title='1'><mark>is</mark></a>a fictional character played by Kevin Durand in the fourth season and sixth season of the American ABC television series Lost . Keamy is introduced in the fifth episode of the fourth season as a crew member aboard the freighter called the Kahana that <a href='drop_aux' title='2'><mark>is</mark></a>offshore the island where most of Lost <a href='uninflect' title='3'><mark>takes</mark></a> place . In the second half of the season , Keamy served as the primary antagonist . He <a href='drop_aux' title='4'><mark>is</mark></a>the leader of a mercenary team hired by billionaire Charles Widmore ( played by Alan Dale ) <a href='null_relcl' title='5'><mark>that</mark></a>is sent to the island on a mission to capture Widmore <a href='null_genetive' title='6'><mark>'s</mark></a>enemy Ben Linus ( Michael Emerson ) from his home , then torch the island . 
First Sergeant Martin Christopher Keamy a fictional character played by Kevin Durand in da fourth season and sixth season of the American ABC television series Lost . Keamy is introduced in tdafifth episode of the fourth season as a crew member aboard the freighter called thdaahana dat offshore the island where most of Lost take place . In the second half of the season , Keamy served as the primary antagonist . He the leader of a mercenary team hired by billionaire Charles Widmore ( played by Alan Dale ) is sent to the island on a mission to capture Widmore  enemy Ben Linus ( Michael Emerson ) from his home , then torch the island .