Level 90 Time Quest

Zoe - Heavens Tear

I reached level 90 (obviously) and started the new time quest. I have reached the point where I am required to kill 3 bosses in Seal of Torment (fb 99 in the sage world).

I know I won't be killing them anytime soon, but I was hoping I could get some info from higher levels on what to expect with them, and what I'll need to kill after that part of the quest is done.