Lurkin's Blizzard - King of the North

• Kullean Transfig Aspect of Biting Cold on Amulet. Aspect of Shredding Blades also OK. Aspect of Mind's Awakening is also good if you wanna be defensive
• If you have enough crit chance, run attack speed there. Remember Stalagmite grants 15% so you only need to hit 85% sheet crit
  
• You will need to adjust how many Mana regen and Resource Cost reduction rolls you have based on your gear. Once you have a seal with (+ mana when a mastery skill is triggered) you are basically set.
• Resource cost reduction tempers on Jewelry help. Mana regeneration affixes on armor do as well.
• This build use Resource Generation Frost Nova so when mobbing things are chill
  
• Iceheart Brais can be swapped for Aspect of Disobedience pants
• If you want to or are already using a STAFF you can drop Aspect of Arcane Ward for Aspect of Heavenly Strength, run Lingering Aspect on the staff, Aspect of Merciless Cold on the amulet, Aspect of the Frozen Wake on gloves, then Blasting Aspect on ring. Sunderfrost Aspect becomes the odd man out.
• If you want to run Blue Rose cuz you get a really good mythic one, you drop Aspect of the Frozen Wake
• Blue Rose can be ran as a ring, preferably if you find a Mythic one

Berú of the Threefold set is just insanely strong... I am not sure that Phoba of the Frozen Sea set is worth it yet.

Berú of the Threefold allows you to run a Seal with + Mana when a Mastery Skill is triggered that basically solves all mana costs in one swoop