Easiest level to get this on is the first / tutorial. After you learn about shadow creation and leaping you will drop down a small ledge and be given the tutorial for abilities.
Select Twin shadow (bottom right on the ablitiy wheel) and tag the furthest of three guards in front of you. Hold your ability button to activate twin shadow as this is being done walk towards the nearest guard and tap E after twin shadow procs your achievement will pop not long after.
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