Five additional returning characters have been confirmed for Soul Calibur III, according to Famitsu. Cassandra, Voldo, Raphael, Astaroth, and Ivy will join the five previously announced characters, Mitsurugi, Taki, Zasalamel, Tira, and Setsuka, when the game is released in Japan this fall.
Aside from minor costume updates (Raphael now wears a green costume with a red cloak), there seem to be no significant changes to the characters nor their weapons.
Soul Calibur III is being developed exclusively for the PlayStation 2. For more details on the game, check GameSpot's preview.