Oswald is the fourth character you’ll get to play as in Odin Sphere Leifthrasir. He’s been gifted with a powerful Psypher sword called the Belderiver, and he lives to serve his foster father, the fairy Melvin. He believes that he was abandoned by his biological parents, and he lives life without a true sense of self or purpose, only finding solace in the hope that he is aiding Melvin in his ambitions.
Oswald is a very swift attacker, and his unique property is that he can enter a state called Berserk Mode. This allows him to move faster and attack quicker. His attacks also become a lot stronger in this state. It’s very easy to build up the Berserk meter, so I highly recommend using it whenever you can, especially during boss fights.