Actual description of achievement:
As hades apply Blight on your enemies to augment all four of your abilities in one game.
Blight is Hades' passive ability. When he basic attacks an enemy he applies blight to them for five seconds. Essentially what blight does is increase the effectiveness and power of your abilities.
The achievement requires you apply blight to augment each of your abilities in a single game. To break it down further it would look something like this:
Basic Attack +
or ability 1
Basic Attack +
or ability 4
Basic Attack +
or ability 2
Basic Attack +
or ability 3
The order you do your abilities does not matter so long as you augment all four abilities in a single game.