The Witcher 2: Assassins of Kings -
"Enter the mist. Your first task will be to battle the standard-bearer of the Dun Banner as an Aerdinian soldier. You'll be slower than normal, so use your light attack and parry rather than dodging. You'll then assume the identity of a member of the banner. Run straight back to your lines, weaving to avoid palisades. Inform the visitor of your plight. You'll then become Seltkirk. Use heavy blows and blocks to defeat the knights. Return to Geralt's form and convince Seltkirk to stand aside.