In the Legend Stages section, there's the Crown/Level Difficulty system, which buffs up enemy magnifications of the Subchapter by a set multiplier.
can, at best, make a stage much easier to handle and, at worst, turn it into a complete joke, especially if said addition is something that's easily accessible by many players. Note: As the game is constantly getting updated with brand new content, take every single stage here with a grain of salt as it's likely that a newly-introduced unit/True Form/Talents/Mechanics/etc.
Don't be fooled by the game's looks, The Battle Cats has plenty of these kinds of levels.