Have fun not dying while everything else dies in front of you. (And look good while it happens).

Damage reduction with warcry, arcane [Guardian], and [Adaptation] all active should [Reach] just over 99%, and your arcane grace will keep you topped off without a need for healing items.

Swap [Narrow Minded] for [Primed Continuity] if you'd like to share this build with teammates, although that hurts yourself in the process. You would be able to save an Umbral forma this way, however.