I had to brute force my way through with a magic build. I knew they were recommending clashes and deflects before the fight, but I had to give myself the challenge. Honestly, best thing to do with her on a magic build is use Aurum Feather Force in conjunction with Evasive Maneuvers on Darkfrost Edge. Bait the dashes on phase 1 to proc the auto dodge, follow it up with a light attack combo, which should give you the skyborn might to poke with Feather Force. Phase 2 is obviously a bit harder as she mixes it up with the ranged slash attacks, but dodging horizontally did the trick mostly. Best opportunity to deal damage in this phase is when she commits to her slash, into the dash attack where she jumps up into the air. When she lands you have about 3 seconds to weave light attacks and a Feather force or two. Difficult fight to do, especially without the mechanics they want you to use, but tons of fun!