Captain Magh was the commanding officer of a Klingon warship that intercepted Enterprise NX-01 when it entered Klingon space in search of Arik Soong and his Augments in 2154. Enterprise managed to disable Magh's ship and escape by using the grappler to damage one of the nacelles on his ship. (ENT: "The Augments")
Magh was played by Mark Rolston.
His name comes from the script.