Warhammer - Swords of the Emperor Short Story - Duty and Honour by Chris Wraight

As a border dispute with Bretonnia threatens to erupt into bloody war, Reiksmarshall Kurt Helborg agrees to settle the conflict the honourable way – through single combat with the Bretonnian commander. Outclassed by the goddess-touched Grail knight and fighting a losing battle with his life on the line, Helborg must decide which is more important – personal honour or his duty to the Empire.