Socrates said "For instance a grip with the Anime series Sacred Blacksmith was the protagonist Cecily was too weak. She couldn't even hold a sword and she was a Knight. She had a bit too many flaws."
The anime doesn't really do her justice -- in the novels, she's not played for laughs quite as often. Anyway, she's not really so bad, but compared to Luke (who is ridiculously overpowered), she looks completely incompetent.
Which brings me to my
actual point: Characters who are ridiculously overpowered will make fools out of reasonably-powered characters if a general power level is not established early. If we had gotten to see Cecily and the knights winning against some reasonable opponents beforehand, it would have been more obvious that the demons were horrifically strong. As it was, it just looked like all those knights of Housman were all incompetent mooks.
In an example that is a little more relevant to the discussion of game creation, I played in a tabletop game where the GM thought that it would be a good idea to make the first fight of the game against a duo of overpowered supervillians. (It was supposed to be unwinnable, and provide the motivation to make these guys our main rivals.) There were two mistakes here:
First, because the players didn't have a good grasp of the campaign's actual power level, this caused many of the players to start min-maxing their characters, making the less ridiculous fights the GM put in front of us later continuously less challenging, and the characters generally less fun to play (since the players did nothing but push their speed and attack to the breaking point, and put nothing into new skills or interesting abilities.) The game's fights became nothing but, "Get as many turns as you can, and do as much damage as possible with each hit." This doesn't sound that bad, except that some otherwise less challenging baddies could be immune to this tactic.
Second, we actually managed to scrape by a win, making the whole thing a bad precedent.
The moral of this story: be careful when and how you deviate from the intended power level of your game/setting/whatever! A swordsman who can slice a guy in half with a single blow looks really awesome until he's faced with a dragon with sword-resistant scales.