Just beat this guy solo with a lvl 63 guardian after about 5 runs. strategy: i went in and popped all possible cooldowns and then just kind of hid up on the bridge until i was able to heal up to full health again letting my main ally fight him while i would flip between trying to do as much damage as possible in about 5 seconds before my health was down to 25% and hiding on the bridge until i was able to heal again. did that about 3 times before the finally died