AssassinationsHalo: Reach. Everybody remembers the old style assassinations. All they were were melee kills from behind, rewarded with a ninja medal. The old ninja medal is still there, but for a true Halo: Reach style assassination, you have to hold the Left Bumper when you approach an enemy from behind. This will cause your character, Spartan or Elite alike, to catch your opponent off guard end deliver a fatal blow using either a knife or hidden Energy Sword, species dependent, to kill your foe.
This feature is purely for bragging rights and can leave you in a jam if you use it at the wrong time. You can't cancel the animation, which is a good second or two long, and you are not invincible during it, meaning if you choose to do the flashy animation at the wrong time, you'll leave yourself open to be killed by the enemies nearby teammates.
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