Heartrenders are Grisha of the Corporalki order. They can use their power to damage a person's internal organs. Their ability ranges from slowing a person's pulse to snatching the air from their lungs. The target must be in their line of sight.
In the Second Army
Corporalki require the most training and study of all the Grisha orders in Ravka. All Corporalki study the same classes together for the first two years of their education at the Little Palace. After two years, Heartrender and Healer training diverges; Heartrenders study to become soldiers.
Heartrenders manipulate the body on a molecular level, usually to harmful effect.
- Lungs: They can take the air out of a person's lungs and keep them breathing as long as they're in the Heartrender's influence. They can also crush a person's lungs.
- Heart: They are able to induce heart attacks, slow the heartbeat to the point of loss of consciousness, or quicken the heartbeat to dangerous speeds.
- Hampering healing: They can slow the healing process, rather than quicken it.
- Influencing emotions: By encouraging the release of certain chemicals in the body, Heartrenders can influence a person's emotions.
Under the effects of jurda parem, a Heartender's abilities are heightened to an extreme level. Nina Zenik claimed that just one Heartrender on parem would be able to tip the scales of a war between nations.
- Mind control: They can force a large group of people to follow their verbal commands unquestioningly.
- Other Corporalki abilities: A Heartrender becomes able to perform great feats of healing and tailoring, better than most regular Healers and Tailors.
- Enhanced sight: By increasing the range of their sight, parem allows Heartrenders to affect targets at much farther ranges than usual.
- Like all Grisha, Heartrenders cannot use their abilities when the movement of their hands is restricted.
- They require sight for their powers to affect their targets. Anyone too far away, obscured from complete sight, or out of their range of vision cannot be influenced.
- Heartrenders' abilities do not have any effect on animals.
- Fedyor Kaminsky
- Nina Zenik (former) 
- Sergei Beznikov
- Tamar Kir-Bataar
- Tolya Yul-Bataar
- The Witch of Fells
- Shadow and Bone, chapter 4
- Six of Crows, chapter 14
- Siege and Storm, chapter 1
- Six of Crows, chapter 6
- Six of Crows, chapter 5
- Crooked Kingdom, chapter 15
- Six of Crows, chapter 41
- Nina Zenik is able to instantly heal herself and Matthias Helvar from multiple fatal bullet wounds (Six of Crows, chapter 41) and permanently Wylan Van Eck to look exactly like Kuwei Yul-Bo (Six of Crows, chapter 45).
- Six of Crows, chapter 40
- After recovering from the effects of parem, Nina's abilities changed markedly. She lost the ordinary abilities of a Heartrender, and gained an affinity for manipulating dead and decaying flesh and bone, becoming known as a Corpsewitch.