[Open Hearted Captain]
[Unlocked all costumes]
Most characters gain costumes with proficiency. Some may gain them at F, some at B and some at S. You will get this on the way to Instant Kaleidoscope. Bear in mind not all characters have more than 2 costumes (in particular, those that are new to DW7, SW3, or MO.. although there are exceptions such as Gracia). If you get someone to S in Musou Battlefield, it will not count as having actually used the character, and thus you'll need to play them once in story mode to actually unlock their costumes (and wallpaper).