Mechanics
The build revolves around a "Cast on Crit" PoE-type of playstile. We use Frost Claw to proc Lightning Blast on crit through Dragorath's Claw while simultaneously procing Ice Barrage from Power Word: Hail 3/3 for single target and help with clear.
This results in a somewhat mana intensive playstyle but through Mana Strike we just hit 2-3 times on a pack to refill all our mana and continue.
Since we are procing Lightning Blast and Ice Barrage we don't need them on our skill bar so we use those spaces to put our movement skill Teleport and unsepecialized Runic Invocation to cast buffs on ourselves.
The buffs we use are:
Skill Rotations
Prepare for battle by casting Reowyn's Frostguard using Frost Claw and Frost Wall and then proceed to spam Frost Claw and use Mana Strike when needed.
Try to put Frost Wall on top of the enemy as this will put a Brand of Trespass on them through Brand the Invaders 1/1 which will proc our Celestial Doom 7/10 bonus. Don't forget to pass through it to proc a Flame Ward for the 30% less hit damage.
If you can micromanage it, you should recast Frost Wall, taking advantage of it's Howling Rift 1/1 node before 4 seconds so that when you pass though it again you gain 4 seconds of Haste and Frenzy through Boosted Kickoff 2/3.
If you want you can intermittently cast Covenant Arc to help DPSing or refilling mana with Mana Strike.
Since Frost Claw is a projectile skill which pierces all enemies, this doubles down as our single target and clearing skill, so spam it as needed.
While clearing the monolith you should cast Frost Wall ahead of your path, so as when you pass through it you get Haste and Frenzy, with this in mind you can chain them along the path throught the whole monolith for faster clears. Also remember to cast Reowyn's Frostguard every now and then (the buff lasts 13 seconds or unitil you lose all your ward) while you lay down these Frost Walls.
Defenses