User blog comment:The Milkman/The Writing of the Ending/@comment-24174486-20120726200543/@comment-5337704-20120823123222

Dues Ex, its really a matter of symantics. It is like decimate, the meaning of every ten killed, but used loosley Dues Ex can almost be used if you use the whole series, but since half the plot revovles around the cruicible, I fail to use it.

If you played Halo 2 the creature that captures you in the ocean is a prime example of one. He comes out of no where, and is used to further the plot, but outside of it, he has nothing to do with the story at all. I could say the same thing happens with the thorian, but he was explained right before you search for him. There's a line between a plot twist (thorian), dues ex (halo 2 creature) and an odd plot (me3 AI). I can't say ME3 AI was a plot twist per se, as you really didn't know what the catalyst is, but you do know it will be activates.