After trying this a multitude of times, I've found a great many things wrong with this boss.

Visually things are not being telegraphed correctly.

The tornadoes that fly across the room sometimes do so without the purple line marker on the ground. During his dive bomb attack, I've seen him hit the ground before the circle even appeared. The weird things that jump on you can also hit you outside of their landing area. Purple fire that appears on the ground can sometimes be invisible and just kill you outright. His massive Cyclone AoE damage happens significantly after the animation ends, causing for a weird window to try and time invincibility (because some classes have one chance at invincibility with a pretty decent cooldown). His other dive domb twirl attack also can hit you outside of the lines on the ground. Same with the slashes he shoots out after the wind when he lands in the middle.

The elite enemies that you have to kill to get the souls attackable have a breath that shoots out at you with nigh invisibilty. His phase transition has a multitide of delayed attack animations that don't line up with whats happening on screen.

Think of this as a log because I do hope with coming updates, these bosses get better attack data KR needs all the info it can get.