This build doesn't particularly need much in the way of explanation - [Rage] for energy generation, [Quick Thinking] as a very last resort to prevent death, but between Arcane [Guardian], Defy, Iron Renewal, and the constant healing from Renewal should be enough to withstand extreme amounts of incoming fire.

Alternate healing sources ([Bhisaj-Bal], [Healing Return], etc.) can push the durability even further, but are certainly optional.