Sacrifice (voidwalker ability)

Sacrifice is an ability of the Voidwalker, a warlock minion. It consumes a portion of the Voidwalker's health, granting the warlock an absorption shield that is similar to a priest's Power Word: Shield ability. The ability consumes 25% of the voidwalker's base health, so as long as the voidwalker isn't near death, there is very little chance that the use of this ability will kill the demon. The duration of the Sacrifice shield is 30 seconds.

Sacrifice is learned automatically by your Voidwalker at level 28.

Tactics
It's very useful when using Hellfire, making a getaway or to extend your life in PvP combat. Using Sacrifice in Battlegrounds is especially useful because when you die and resurrect, you get your Voidwalker back without having to re-summon it. Even if you are not Demonology specced, this ensures that'll you be able to sacrifice him at least once without having to re-summon.

Having Fel Synergy will allow you to heal the voidwalker back for the health he loses very quickly and makes the use of the shield a non-issue as long as the pet is in reasonably good health.

It is possible to summon another demon while under this shield. In an emergency you can Sacrifice your Voidwalker, resummon it (it will now be at full health), and Soul Link with it again.

Trivia
This spell was known as "Sacrificial" Shield during the Beta tests.