SidVanHalen wrote:
There are many ways of implementing Deus ex Machina-
1. He takes some super techno device from his pocket and escapes
2. A love interest, who had so far not shown any interest in being an accomplice, suddenly shows up and takes care of the guards
3. He foresaw all of this happening/possibility of this happening and had some safety mechanism in place.
4. A character, barely introduced, comes out and tells the thief that he'll help the criminal if he can get his hands on some documents from the safe.
Honestly, I get the idea you don't really know what 'Deus ex Machina' means, from one or two of these.
1 is just bad, if that's all there is to it. If you're going to have a super techno device, make sure it's established previously or at least established that the protagonist is likely to have such a thing. Fred Bloggs needs to tell the reader ahead of time that he has a grappling hook, because he's a mild-mannered refuse collection technician and there's no Earthly reason he would own such a thing. If he pulls it out to escape from a predicament, the reader doesn't think "Oh, thank goodness Fred escaped", they think "what the hell is he doing with a grappling hook? That had better get explained!". Batman doesn't need to tell the reader he has a grappling hook because he's Batman.
2 isn't necessarily terrible, but it needs to be explained afterwards, otherwise you essentially set fire to any character development you'd spent on the love interest and they're no longer a believable character. If the story hinges on an unbelievable character, then that catches fire too.
3 isn't even remotely a Deus ex Machina device. If it's pre-planned by the character, it's pre-planned by the character! Again, though, it needs to be obvious to the reader that it
was pre-planned and why. It's fine to explain this after the fact, so long as you don't contradict earlier parts of your story ("Oh, yes, I came here five weeks previously to hide this gun here that I need now to escape" "but five weeks ago you were on the moon!" "a minor detail..."). In fact, a large quantity of detective fiction, particularly the archetypical Sherlock Holmes stuff, works in this mode; the detective goes into the room at the end of the story without the reader having a clue what's going on, denounces the villain and the method out of the blue, and
then goes on to explain how he worked it out. The important thing is that the build-up - the important clues -
were in the story before this point, and the detective doesn't say anything at any point that contradicts the story so far, nothing that's impossible.
4 is fine for the beginning of a story, but totally sucks for the end of one. At the beginning of the story (or at the beginning of a story arc/subplot), you've not got any real set-up to the jam the protagonist is in, and thus there's no mandate to do anything particular with it, you can use it as a vehicle to both introduce the protagonist and his profession, and also introduce this other character, and start the main plot rolling with his request and the debt the protagonist now owes him. At the end of the story, however, the reader has been built up to this moment throughout the plot, and he is owed a decent denouement wherein all the major loose ends of the plot are tied up in a satisfactory manner. "Hey, here's a get-out-of-jail-free card for no reason" isn't a satisfactory manner; your spontaneous character may not be acting out-of-character, but he's an outside party to the contract the rest of the plot has made with the reader, and as such he has no part in the fulfilment of it. After he's helped the protagonist out he's owed a favour, but since the story has ended, there's no way for the protagonist to pay him back.
I'll agree with the other guys in plain terms, just in case there's any doubt: a Deus ex Machina at any important point in the plot is
just bad, no two ways about it. It's true that they're not absolutely universally bad, the world has space for serendipity and fortune, but stroy arcs absolutely cannot be resolved by it or you're wasting your time developing them in the first place, and the reader is wasting his time reading them, because they're basically not stories.
