A little rant about A12. I try to not spoiler to much.

Not long after the ultimate attack, the boss will open 4 portals, where usually 4 damage dealers or 3 damage dealers and the offtank do enter.

What you do and what you see there is an important plot belonging to the cutscene before that fight.

But the way the battle is designed, most tanks and nearly every healer will never see this piece of lore.

It would be nice, if in the future these little phases could get designed in a way, that the entire party can participate. In that little part it would generally make more sense, if the boss would teleport away and back from the battle arena.