By Your Powers Combined...
The Ascendant Council in Bastion of Twilight seems designed to play with all of our well-honed reflexes with regards to running away from stuff. At various times we're required to run into fires, tornados, and void zones to avoid even worse effects. This, combined with distinct phases with different sets of enemies, makes for a unique and fun encounter.
Note to insane cult leaders: next time don't arrange your defenses so that their strongest abilities cancel out. Feludious would have no trouble freezing us to death if we weren't able to dry ourselves off in the toasty glow of Ignacious' fire. Ditto with Airon floating us above Terrastra's earthquake. We were able to work through those phases and learn a number of tricks for survival while pursuing the goal of balanced dps on all the bad guys.
In the final phase the golems merge. It was just a matter of arranging positions to avoid killing each other and burning the monstrosity with everything we had while healing through raid damage that quickly goes from 'that tickles' to 'volcano of pain'.
Once past the monstrosity we were just a hop, skip, and a jump away from looking Cho'Gall right in the eye(s). I have a feeling he's not really the one in charge here...