How do you unlock the revenant in Mass Effect 2?

Answer 1

Your character must be able to use machine guns (aka soldier). When you get to the derelict reaper halfway through the game, you are allowed to choose either another weapon type (for those with limited options) or a very powerful version of the weapons you are allowed to use. If you already have machine guns you can choose the Revenant Light Machine Gun. Make sure you get the accuracy upgrade if you choose that weapon!