Permafrost
Your auto attack damage grants you an absorb shield equal to 50% of the damage dealt.
Tree position
In the Blood Death Knight talent tree, Permafrost sits in the Death Knight class talents, row 4 of 10. It is a single-point node.
Connected above
The tree draws a line into Permafrost from Gloom Ward.
Connected below
Permafrost leads on to Icy Talons, Death Notes and Anti-Magic Zone.

Death NotesRaise Ally costs 30 less Runic Power.
Anti-Magic ZonePlaces an Anti-Magic Zone for 6 sec, reducing the magic damage taken by party or raid members by 15%.
Same row
Also on this row: Coldthirst, Proliferating Chill, Veteran of the Third War, Death Pact, Brittle and Blood Bond.
ColdthirstSuccessfully interrupting an enemy with Mind Freeze grants 10 Runic Power and reduces its cooldown by 3 sec.
Proliferating ChillChains of Ice affects 1 additional nearby enemy.
Veteran of the Third WarStamina increased by 20%. Damage taken reduced.
Death PactCreate a death pact that heals you for 50% of your maximum health, but absorbs incoming healing equal to 30% of your max health for 15 sec.
BrittleYour diseases have a chance to weaken your enemy causing your attacks against them to deal 6% increased damage for 5 sec.

Talent trees
Permafrost is in the talent tree of 3 specializations. Death Knight: Blood (Tank), Frost (DPS), Unholy (DPS).
Permafrost Changes by patch
Tracked changes to this talent between game data builds, newest first.
- First tracked in the game data (patch 12.1.0)