This boss is a pain in the rear, it can be done but it is really difficult with the way she moves about. Have a watch at the tactics here on Youtube :

http://www.youtube.com/watch?v=BNW6c9FVDNk

Essentially you have to keep moving, watch out for her shadows when she is up high, gives you an idea of where she is going to land. Dont attack to many times when close to her or she hits hard. Use your grappling hook to get close and do a quick combo then back off. If your positioning and timing dont feel right then skip the attack till she moves. She does actually have specific places where she moves to in the room. Its literally just learning the sequence. If my mind serves me right you can also hit her with your giant shuriken thing when she is perched on the wall to get a bit extra damage in.

Cant help you with a save though as I have it on PS3, she is actually one of the hardest bosses in the game with being in such an enclosed space.

Basically just follow the video iainmet posted

learn her moves/pattern and use the dash to your advantage, she can be irritating at first but she's actually fairly easy once you get everything down

Also: Darksiders kicks ass, fantastic game

Pretty much this and what everyone else has posted, you must perfect your dash timing. I played through on Apocalyptic mode my first playthrough. This game is better with a gamepad and is well known to only work with a real XBox 360 gamepad (for some reason about which I'm not really sure).

You can beat her with 20% life going in. Just be ready to "hook shot" to her and get your whacks in when it's time, if you think you stalled too long to be safe, don't do it. Don't get greedy with your attack chain, either, 3 shots is normally all you have time for, then you'd better be beating feet.

Also, be ready for phase 3, on Apocalytpic mode I was not, fucked it up, and had to start all over.

If you learn how to do it, she's actually one of the easiest bosses :P Just run away when she teleports over you and get close to hit her when she goes to a corner to rest. Rinse and repeat, she'll be dead in no time and with very little effort :P

yeah, i figured her out pretty easy until she caught me by surprise in the final phase dropping the "bombs" on me, had to replay after that.

Two things.

First of all, no "boo hiss." Darksiders is amazing, and underappreciated. Can't wait for the sequel.

Secondly, I haven't gotten to that boss yet, but one thing I HAVE learned is that blocking is useless and health restoration items are a poor fallback. Learn to dodge. A LOT. Getting hit is a terrible idea in this game, even on regular difficulty. I'm about to head into Silitha's (sp?) realm, playing on regular difficulty, and I have purchased exactly two health restoring items.

I totally agree with Darksiders being amazingly charming. Here's a comic for you:
http://penny-arcade.com/comic/2011/06/03

Also, yeah, I maybe used 2 health restore items on Apocalyptic. Actually Apocalyptic was great training for the whole "just don't get fucking hit" thing because you are forced to learn to dodge everything before you even see a real boss (not counting the prelude as that fight can only really go one way).

Are you actually playing it with the keyboard controls? I feel so bad for you, I couldn't even touch the game until I found my controller. Of course, my camera was ridiculously sensitive even at the lowest setting (move your mouse slightly and it loops 180 degrees).

Regardless, it's an excellent game, unfortunately I don't think I can be much help. Hopefully the other posts helped you beat the bastard.

Thank you all! You actually gave me new hope I could beat that boss, if it's only a matter of learning a move pattern. After all, Tiamat was not a walk in the park... until I learned how to place myself! ;) I'll try again on my own this week-end, but yes, Darksiders is an excellent game.

iainmet> thanks for the vid! I'll make sure to watch it before my next try.

orcishgamer> I think that finally my main problem was that I was too "greedy" on my combos. I should learn to be more patient. But boy i will feel relieved when she will be dead! ^_^

Ruenhamster> Ha ha, in fact, the "boo, hiss" was for the "on Steam" part of my sentence, since I know some people don't like Steam ^_^ Darksiders IS a great game, and I will definitely follow the development of Darksiders 2. And you're right, blocking IS useless, I frankly have never used it apart from the minigame that forced me to kill a certain amount of enemies with the blocking combo. And that was a pain in the ass. And I never found useful to buy restoration items, since I've always found enough green chests to replenish my health ;)

Penutbrittle> yeah, unfortunately, I play it on the keyboard. Not an easy task, I must admit, but I don't want to buy an xbox controller. I have an excellent Logitech pad, but using it only results in my camera always pointing to the sky, making the game impossible to play...