For those of you that have the priviledge of not knowing what Deus Ex Machina means, its literal translation from Latin is "God of the Machine" or in plain old English "Are you ****ing kidding me?" The whole purpose of Deus Ex Machina is when the mangaka of a series throws their hands up in the air and comes up with something so out of left field in order to wrap up a story or a conflict in the show that a person's groan can be heard in space. Now it can be debated why a mangaka does this in the first place whether they made a too convoluted plot that the characters can't get out of or they accidentally made the villian in a story arc too over powered. The end result will be the hero or heroine pulling a miracle out of their ass.
Now you may be asking yourself "Wales, you've kicked a lot of whole sale ass for a lot less. Why bother discussing Deus Ex Machina? It's been a common plot device in literature, films, and any form of entertainment for centuries. Why now?" The answer is a simple one. I recently became a fan of Fairy Tail from the insistance of my friend here obscurefan. However, after reading some of it, he pointed out moments of Deus Ex Machina and I couldn't help but to acknowledge that Hiro Mashima did not know what he was doing while writing it. Or maybe he did and he fell in to one of the two categories I mentioned in the previous paragraph. After our conversation, I did some reflection and recalled many different anime and manga instances where victory was pulled out of thin air.
I honestly don't want to waste your time and mine with the hundreds of examples where the heroes can pull off a flawless victory despite not having any magic/energy/chakra/whatever fuels the protagonists. Instead, I would prefer to list ideas that can be seen where Deus Ex Machina takes place even then it would take too much effort and cause my headache to split into the San Andreas Fault Line. I know it's kind of lazy to do this right now but I would rather you all, the anime community, be aware of series that fall victim to this lazy form of writing. Its sad since most Shonen manga fall culprit to the machine.