From "Devil Hunter" (normal difficulty) or higher, after beating the final mission beat the enemies during credits: As Nero you must protect Kyrie, it'll unlock the EX costumes for both Nero and Dante. As Lady (beat mission 20 with rank A or more) you must defeat 20+ enemies. As Trish (beat mission 20 with rank B or less) you must defeat 20+ enemies. As Vergil you must defeat 30+ enemies.