This can first be obtained in Chapter 4
From the very start of the mission, make sure you have unlocked the Kunai skill by first ensuring you have enough Scrolls. It’s under Offensive techniques in the skill menu.
Next thing to do is run around the corner and you will see 2 guards on the ground, and an archer elevated on a platform. Run towards the campfire when the coats is clear, and hold
to throwna Kunai at a guard on the ground. The archer will see you and fire an arrow at you, instantly killing you. Your achievement should unlock.