My new strat on kael is pop all trinkets and stuff get him to 50% should go fairly fast. Then when he leviates you press your follow button and have everyone come back to the entrance. Since all your guys are moving together the bubbles should all move toward you. Just fly around the room for a bit healing when needed. After ~30 seconds you get put back on the ground and you can dps him more. It used to be a race b/w the time I was leviated and him dying or me dying. With this new strat I can down him on heroic without bloodlust easily. One things that also might help is summoning your fire elementals to dps him while you run around. I can try and post a video if this made no sense.