Legend of the Millennium Dragon? More like Legend of the Derp That’s Not Actually Important At All And Doesn’t Feature In Most Of The Movie.
Seriously the dragon was built up as this epic thing that will end the war but when it actually appeared it literally kept crashing accidentally on walls. And not in a way that was supposed to show how it was stupid (and it didn’t speak or show any intelligent thought, and no, the criss-crossed eyes are not an exaggeration from my part). And then they didn’t do anything with the dragon for like… 98% of the movie, the protagonist just used it as a transport.

The characters were awful*, the plot was just plain stupid and outside one major twist predictable and cliched, but then the animation and designs were actually quite good and interesting. Seriously. Like they were good enough that I might want to draw them at some point. So I can’t say I regret that I bought it from the bargain bin because it could have been a lot worse but damn, wasted potential.

*As an example we have these rural people who are called “oni” (as in, the monster) by their enemies and the oni guys take that as an insult because they’re assigned this name that means like “hiding monster” or something because they hide themselves in their nature village, which I could agree with… EXCEPT THESE GUYS FIGHT ALONGSIDE HUGE MAN-EATING DEMON SPIDERS AND GOLEMS AND USE THESE MASKS THAT MAKE THEMSELVES LOOK LIKE REAL MONSTERS AND KILL THEIR ENEMIES WITH ELEMENTAL BENDING so really at that point you really have no excuse against your enemies calling you monsters. Just saying. And yes, that was played totally straight and none of that “huge man-eating demon spider” stuff was explained or even vaguely touched upon. All that just conveniently wasn’t mentioned when the plot had to convince that the oni were just hated for no reason and totally peaceful.