Devil May Cry 5 (DMC5) has one unlockable costume for every playable character. There are 3 characters total so 3 costumes to unlock.

How to Change Costumes:

Beat the game on Dante Must Die difficulty to unlock the “Super” Costume for every character.

Then you can change the costume via mission select before every mission.

That’s all there is to it. To unlock Dante Must Die you have to beat the game on Son of Sparda difficulty. To unlock that you just need to beat the game on Human or Devil Hunter mode.

After having finished Dante Must Die it will tell you about having unlocked the “Super” costumes of every char. Then go into mission select. Pick any mission and it will let you change the costume.

Super Nero Costume

Super V Costume

Super Dante Costume

These outfits also come with infinite devil trigger but be warned, using them gives you a -80% score decrease at the end of missions so S-Ranks are impossible to get.