ultimate mode

Hey, I have a question about ultimate mode. (This is probably a stupid question) I was curious what was different about it than other modes so I checked a video on youtube, and saw that everything looks like a dark version of the monsters you find in other modes. Is it part of the story, or a cool feature that was added for whoever got that far in the game?

Ultimate was added as one of the new features of Ver.2, although its purpose in the story has never been entirely clear. The common theory was that Ultimate takes place at a slightly later date, after Pioneer 2 has landed on Ragol (hence why Ultimate Pioneer 2 has blue sky and not stars). Supposedly, since it's sunset in the Forest and all, Ultimate takes place at dusk, which is when the uber enemies appear.

Thanks.