These codes will help you to unlock the characters for the Versus mode:
Mihawk: pP72dQw83R7Wdfnf
Nami: GjfrK92hjyzFB7BC
Trace: P9wRrM9Bw86cK528
Enel: Zzqs6PLNWqwblXBH
Kuina: xLtwnrJ1VKLmSwCg
Crocodile: VBbPVJDcZM9NyNMf
Sanji: m6mzsmwWg7618qgL
Wapol: byfyrsCwFRZx9dDZ