Surviving the last sixth round | 13: Devil's Dalliance DMC: Devil May Cry Guide
Last update: 11 May 2016
The last round consists of three battles. First, you'll fight a Ghost Rage. Activate angel mode, what let you avoid his attacks. To hurt this beast use angelic weapons (Osiris, Aquila). Don't let him make too many attacks and run him into corner.
Second part is an encounter with Blood Rage. In this case you need to activate demon mode and use demonic weapons, like Arbiter and Eryx. In my opinion, gauntlets work better.
The last part is a battle with both those beasts. You can eliminate them in random sequence, but pay attention to what the one you're no attacking is doing, so he won't surprise you. As it's a very end of the mission, you may use Devil Trigger.