Well, aside from all the flaying criticism some of you punks decided to actually give me some advice. After countless nightmares about Beowulf including many weeks of counseling and many soiled bedsheets, I have finally beaten this incredibly jerkfaced boss of jerky jerkness. Who sucks.
Battle equipment: Rebellion, Ebony and Ivory, Swordsman style (level 2) Large life star, a few yellow orbs never hurt anyone, clear mind, patience.
When the battle stars, you will be facing this ugly titan, and two walls will be on the sides of you. Unless you run to the side of Beowulf as soon as the battle starts, you'll be caught head on in his attack with not much to do, so pick a side (I always chose the left) and run diagonally forward. Now, a lot of people say, "Get out of range of his three piece combo". Don't listen to them, they're ugly.
When Beo rears back for his three piece combo, wait until the last second, air hike, and use Ebony and Ivory to hover until he throws the third punch. Slam down on him with the triangle button and Rebellion equipped. If you were lucky enough to hit his obese eyeball, run/roll/float/tunnel(whatever works best for you) and get behind him, because he'll start thrashing around wildly. Go Devil Trigger if you can, and beat the crap out of him until he regains focus. If you didn't hit his eye, hit him until you feel like he might make a move again, and back up to a safe distance (you will have to be a little farther away than his foot in your mouth to be able to air hike above his combo). Bring yourself out of Devil Triger, and wait for his next move when you are done pounding on him, whether you hit his eye or not.
You need to stay relatively close to Beowulf at all times, except for when he stomps the ground causing a nuclear explosion that blows up half of Asia, and when he roars and spreads his wings which has the same effect...
Occasionally, Beowulf will get down on all fours, when he does this, target him, and right as he's about to hit you, hold right or left and push the X button to roll out of your way. He will NEVER hit you if you are brave when doing this, because even if he bumps into you while you're rolling, you won't take any damage. He may run to the corner, start stomping his feet until a cage comes down in front of him. This is where level two swordmaster comes into play. As SOON as the cage comes down, hold R1, forward, and push triangle. This will knock the cage into Beowulf before he has the chance to knock it into you. (You have to be close enough to the cage for the sword to knock it into Beowulf). Odds are this will scoot you up a little, so run back after you slide forward if oyu need to.
If you don't have swordmaster level 2, hold down R1, and be prepared to roll. The timing for the cage can be tricky, but right as it is about to hit Dante roll to the direction you see fit.
If he starts glowing and feathers rise up around him, RUN AS FAST AS YOU CAN AND GET UP CLOSE AND BEHIND HIM! IF you manage to get behind him in time, not only will you avoid taking the massive ammount of damage from this jerk's best attack, but you can Devil Trigger and dice him into sixteen pieces. Maybe even 17.
Now, if you slip up and get hit by being too close to him, failed to air-hike at the right time, didn't make it beind him for the feather attack, or whatever...Wait as late as you can to use your Large Devil Star, don't freak out and use it at half-life because odds are it will compeltely restore your health. I'd wait until at least 1/3rd of your health, but if you're brave by all means hold out until the last bit.
The big key to Beowulf is to be more concerned with not getting hit than anything else. Beowulf's not going to walk out because you're taking too long. You have the ability to pause the game, so take it slow and steady, get your timing right, and make sure that if you DT that your hits connect. G'luck.
Hopes this helps if anyone had as much trouble as I did.