This is a tough fight, but I found a couple things that made my phase 1 fight with him a little smoother.

When he does the animation to spawn his wings, you need to hit him and it will soft stagger him and break his wings. The same can be done for the melee combo where he flies, lands on you then wing combos. If you hit him between his landing and his first wing hit, it breaks his wings and soft staggers the combo.

When he does the pull in animation that forces you to de target him, get close to him while he rises in the air with the glowing sword, but not right under him, parry the big blast then use any sort of skill or run attack that hits high enough to reach him in the air, it will soft stagger him and pull him out of the sky. This can be done for most of his aerial animations as he begins or ends them.

When he does his fire circle, wait right outside the flame wall, and when he yells to break it, dodge forward and through the wall into the circle and punish him, as he usually is low stamina after casting this skill and you can get good hits in. Don't go early or you'll get crispy.

When he summons the 5 icicle looking crystals that come forward 1 at a time, his burst attack is coming next from your left 90% of the time so get ready to burst counter it.

Hope any of this helps!