Capcom tries so hard to come up with another battle like Mundus battle 3 in DMC1, but this is seriously just so lame and unnecessary, not to mention how bad Nero's lines are after that.
- Wait for him to attack you with his right fist. Side roll and quickly press O for Nero to use his DB and swing the fist away.
- Wait for him to swing his left fist at you. You'll require some timing for this - Jump and press O before his fist hits you. Nero will fling that fist away as well.
- The False Savior will then collapse. Press O by his head. The end.