Help with Duncan normal mode Sin

I went and did duncan in Hm beat him in less than 5 mins used the same build in NM and duncans defense killed me.I was a sin and for protection from Duncans defense i used Stoneflesh aura what did i do wrong any thoughts?

You do more damage in NM, so that damage is going to get past your stoneflesh aura. Bring a monk along with Life barrier, that should do it.

If you're running people, just ask one of them to bring life barrier, with 12 in protection.

I actually swapped out ebon battle standard with sunsper skill intensity and worked like a charm thanks for the advice though