Flashing Blades

Acquisition

 * Lou, of the Knives (Shenzun Tunnels) -- triggered boss by walking into a pit.
 * Waeng (The Undercity) -- Only during the Assist the Guards quest. He is the guy outlined in purple.

Usage Notes
With sufficiently high Dagger Mastery, an assassin can have this skill constantly active, to keep received attacks to a minimum.