Sacrifice

Sacrifice is the act of giving up something in order to get or do something else or to help someone. Sacrificial magic was considered the greatest violation of life.

When pushed to the brink, even the wild will make a necessary sacrifice for the greater good. Many wisps sacrificed themselves in order to defeat Archimonde at the end of the Third War.

It is said that a sacrifice of life is the only way to ensure the saving of another.

Demon
Experiments require resources. Thorngrin the Tender makes sure that Kael'thas's botanists have the power and essence they need to reveal the naaru's secrets, even if that means untold numbers of living creatures must be sacrificed to obtain it.

Desperate to show his worth to the Burning Legion, Zevrim Thornhoof told his masters he could enslave the formidable ancients who still roamed Dire Maul. When his own power proved insufficient, Thornhoof turned to other living creatures for additional energy, butchering them atop his sacrificial altar and harvesting their essence in their final, agonizing moments.

Fel magic

 * "To succeed, we must sacrifice. And by 'we,' I mean 'you.'"
 * — Forang Deathrattle

Fel magic requires a sacrifice (e.g. a living fish or two, a few strands of seaweed) to fuel it.

Redemption

 * "You seek to cure a child, but know that all things come at a cost. "
 * — Elune

Stating that it is said that a sacrifice of life is the only way to ensure the saving of another, the demon Avrus Illwhisper ensured that no matter what, the moonstones will cure Relara. With his razor sharp claws, Avrus dug into his chest and removed his beating heart, placing it with the fallen moonstones. Miraculously, the satyr did not die. Instead he was bathed in a warm light and transformed into Avrus the Redeemed.

Magecraft
It's typical magecraft to conjure a thing of such beauty (such as a Mana Jade), only to sacrifice it.

Orc
The Temple was the unholy place where Orcs came to make sacrifices to their gods, and the Necromancers of the land gathered to invoke the will of their dark masters.

Paladins
Paladins strongly believe self-sacrifice is a tool to be used for the greater good.

Knights of the Silver Hand
Although the act of sacrifice is not exclusive to the Knights of the Silver Hand, they consider it to be a staple of their creed.

Troll
After the Great Sundering, famine and violence spread until the jungle trolls begged their gods for aid. One god answered: Hakkar the Soulflayer. He gave the jungle trolls great power, but in return he demanded that they sacrifice trolls in his name. As his hunger for blood grew, he ordered his priests, the Hakkari, to bring him physically into the world of Azeroth so that he could feed directly on his victims.

Sacrifices are common place in Zandalari society and Vilebranch trolls are known for performing sacrifices.

Trivia

 * Blackhand (from the alternate universe) sacrificed his own arm to the elements.


 * High Priestess Azil instills terror in lesser cultists so that they will sacrifice themselves without hesitation when their masters command it.