Yes. Do more damage. That's the only way. ilvl 168 is more than enough to do it, you probably got extremely unlucky with your powers or chose the wrong things. I recommend Demo, I find it has the most synergy with the anima powers.
Also the instant summon anima power is super helpful, you can kite the endboss via summoning your voidwalker every 10 seconds, which taunts as it is summoned and survives one or two hits even at over 10 stacks. Works again best as demo, since Aff and Destru struggle with shards.