So, how much damage do the grandmasters do?

I'd like to know how much HP would I need to survive the fight, with or without HB. A lot of people are talking about how to deal with their skills, but no one talks about their damage.

it's because their damage isn't all that high. Unbuffed they only do about 3.3k to me max, which leaves me with enough to survive rather easily. You just have to watch out for the Warrior Grandmaster's "Rage", because it adds a lot of damage.