Grand Marshal's Claymore

Grand Marshal's Claymore is a two-handed sword that can be purchased as a reward from PvP.

Source
The sword is purchased from Lieutenant Jackspring in Champions' Hall, Stormwind City for

Trivia

 * As a notably popular weapon, this same model sword can be seen on many characters, including Justine Demalier, Eligor Dawnbringer, Temura Ence, John Swifty, and Nerus Moonfang.