Unlock Garuganto/Gargant:
Play the game with a memory card with a saved game from Onimusha 3.
Unlock Giramusaido:
Unlock Musaido and reach level 3.
Unlock Gogandantess:
Finish story mode with all twelve default characters, then defeat Gogandantess in versus mode.
Unlock Jaido:
Unlock Normal Genma or Sword Foot Light and reach level 2.
Unlock Jujudormah Ran:
Finish story mode twice as Jujudormah, then defeat Jujudormah Ran in versus mode.
Unlock Magoichi Saiga:
Fight 200 battles in versus mode. then defeat Magoichi Saiga in versus mode.
Unlock Marcellus Modify P:
Unlock Marcellus and reach level 2.
Unlock Marcellus Modify S:
Unlock Marcellus and reach level 3.
Unlock Mega Man EXE's Grand Style:
Unlock Mega Man EXE and reach level 2.
Unlock Mega Man EXE:
Finish story mode as Samanosuke Akechi in story mode, then defeat Megaman EXE in versus mode.
Unlock Mega Man EXE's Bug Style:
Unlock Mega Man EXE and reach level 3.
Unlock Miyamoto Musashi:
Finish story mode as the normal soldier, then defeat Miyamoto Musashi in versus mode.
Unlock Musaido:
Unlock Three Eye and reach level 2.
Unlock Nobunaga Oda:
Finish story mode with all twelve default characters, then defeat Nobunaga Oda in versus mode.
Unlock Oda Nobunaga:
Finish story mode with all twelve default characters.
Unlock Sasaki Kojirou:
Finish story mode as Miyamoto Musashi, then defeat Sasaki Kojirou in versus mode.
Unlock Sasaki Kojirou:
Finish story mode as Miyamoto Musashi.
Unlock Zero:
Collect the Green, Blue, and Purple Crystals as Mega Man EXE.
Unlock Zero's Proto Form:
Unlock Zero and reach level 2.
Unlock Zero's Ultimate Form:
Unlock Zero and reach level 3.