That sucks dude! Practice on Mission 20 to learn how to beat him, he isn't too tough, if you can beat the 9,000+ missions on bloody palace, you should be able to beat him no probs. To start with full health for the next mission, you can screw around with the last enemy on the previous level. So on the 2nd from last floor, just before vergil, kill all the enemies apart from one, then keep taunting to get your DT gauge to fill, and then use the DT to get energy back. Repeat this until your energy is full, and then fill your DT again, then kill the last enemy. Takes a while, but it's better than dying!