Anti-Magic Shell is a death knight ability learned at level 68. It absorbs 100% of the damage of offensive spells for 5 seconds. The caster is also immune to harmful magic effects for the duration of the shell. It does not, however, remove existing magic effects.
Anti-Magic Shell was originally an ability available to Banshee units in Warcraft III. It has also appeared in World of Warcraft, where it was used by the Shadowfang Moonwalkers in Shadowfang Keep (as Anti-Magic Shield), and in Burning Crusade, where it is used by the Banshees in the Battle for Mount Hyjal raid instance.
- Patch 6.2.0 (23-Jun-2015): Anti-Magic Shell now absorbs 100% of all magical damage (up from 75%). However, damage absorbed no longer contributes to Resolve.
- Patch 6.0.2 (14-October-2014): Anti-Magic Shell now restores 2 Runic Power per 1% of max health absorbed.
- Patch 5.0.4 (28-August-2012): Updated.
- Patch 3.2.0 (04-Aug-2009): The tooltip for this ability will now reflect modifications from the Magic Suppression talent.
- Patch 3.1.2 (2009-05-19): Tooltip error corrected.
- Patch 3.1.0 (14-Apr-2009): The amount of damage this ability can absorb is now limited to 50% of the death knight’s health.
- Patch 3.0.8 (2009-01-20): The cooldown has been lowered to 45 sec from 60 sec.
See this subject on the Hearthstone wiki: Anti-Magic Shell