How do 8-mans function?

[Lemon8or]

or with some 8 man content you need to tank swap, for example ultima hard, you get a debuff that gives you more and more damage, so you need to swap tanks periodically through the fight

Does it do more damage to you? The description only says it explodes at 5 stacks. :/ I never noticed tanks taking more damage when I'm tanking or healing it. But yeah, later on, tank swap will be more often. Healer also has a swapping mechanics like Titan EX rotating Gaol or Ifrit EX rotating Searing Wind. Not sure if Garuda EX's Friction rotates as well cause I never heal it.