What does this thing really do? The description says "Inflicts 25.0% of max health in crushing damage on caster. Inflicts 10.0% of max health in crushing damage on caster every 1.5 seconds." So.... it's gonna kill me, right?
In exchange for continuous incoming damage, you get increased fervor and damage/heal output. Note that it is crushing damage, so the damage will be reduced by your armor mitigation plus any wards you have on you. In my experience, any competent healer should be able to keep up with the damage, except maybe in uber-high-damage raid fights.