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Related to Charred
Type Investiture
World Canticle
Universe Cosmere
Featured In The Sunlit Man
This page or section contains spoilers for The Sunlit Man!
This information has the ability to potentially ruin elements of the plot for the reader. Proceed with caution if you have not read this book.
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I need to understand your power sources. These sunhearts . . . they aren’t quite like anything I’ve seen on any other planet.

Sunhearts, known as Cinderhearts when corrupted, are a form of Investiture on Canticle.

Acquisition and Properties[edit]

Sunhearts are made from people who are condensed into power cells while being between Canticle's sun and the core of the planet.[2][3] How much energy a sunheart is made with depends on how Invested the person was, but most of the energy comes from the superheated energy of Canticle's sun transferring to the planet's core and the person's soul resisting that energy.[4][5][6][3][7] Those made from Threnodites on Canticle are made with at least two hundred Breath Equivalent Units.[6] A normal Threnodite from Canticle has only one BEU,[8] which suggest that for every one BEU a person has, two hundred BEUs of Investiture from the sun fills the sunheart.

Sunhearts are cylindrical lumps of smokestone eight inches (~20.5 cm) tall and a few in diameter, and feel like glass.[1] They emit a deep red light.[6] Sunhearts can be broken apart like resin and each piece will continue to glow.[6] Once depleted, they resemble dark glass or gemstones, with bumps on their surface.[9] Some sections can resemble a screaming face.[1] Despite their condensed heat, they can be carried safely.[9] They will float to the top of magma.[10] Charged sunhearts are considered alive by the reckoning of Investiture.[8]


Sunhearts are stable forms of condensed energy and are able to act as batteries or fuel.[9] This can be strong enough to power entire cities.[11][12] Once all of the energy has been expended, the core will dim.[9]

Heat and Investiture can be transferred in or out of a sunheart, though a Connection to the person who made it is required to transfer energy into it.[13][6][14] When taking in Investiture, sunhearts will filter and purify it and will take corrupted or undesired Investiture first.[6][14][15]


Bold one on the threshold of death, take into your sunheart my heat, that I may bless those who still live.

Rebeke reciting the prayer to transfer Investiture into a sunheart[16]

If not depleted, sunhearts can be given a small amount of Investiture, but this normally doesn't give it a substantial amount of Investiture.[5][8] If a depleted sunheart is left back into the sun of Canticle, it will not recharge as the Investiture just passes through the sunheart, instead of being captured by it.[17][7] If there is still Investiture in them, sunhearts can be recharged in the sun, since the soul is resisting the Investiture, causing it to flare and be captured in the sunheart.[7][16]


Cinderhearts are corrupted sunhearts made from a special Investiture.[7] These can be used to create Charred by stabbing a person in the chest with it.[7][6] Once the cinderheart is inserted heat will begin to flare, causing sparks and flames to spray out as the body is burned.[18] The person's pectorals, rib cage, and heart will burn away, leaving seared and blackened skin.[19] The cinderheart will then radiate from the center of the cavity.[18][20] Through their cinderhearts, all Charred are Connected, and can feel the presence of other Charred.[18] Cinderhearts devour the Charred's Identity and Connection in a manner similar to Yelig-Nar.[21]

Cinderhearts resemble a glowing ember that emits a bright light.[22] If the corruption is removed from a cinderheart, they will glow a soft red-orange.[23] When a cinderheart burns something, it will continue to smolder for a long time.[24]


Sunhearts are used by the people of Canticle to power their cities and to an extent, all their individual ships.[11] It’s also likely they use Sunhearts to power their guns. Sunhearts can also be used as explosives, which can be strong enough to destroy a ship.[24]

Sunhearts can have slivers shaved off, which keep some Investiture and can still be used as a power source.[6][25] Charred can use Sunhearts to store a little bit of their Investiture, making them more independent and able to think logically.[6]


  1. a b c The Sunlit Man chapter 20#
  2. The Sunlit Man chapter 12#
  3. a b The Sunlit Man chapter 40#
  4. The Sunlit Man chapter 16#
  5. a b The Sunlit Man chapter 21#
  6. a b c d e f g h i The Sunlit Man chapter 24#
  7. a b c d e The Sunlit Man chapter 45#
  8. a b c The Sunlit Man chapter 23#
  9. a b c d The Sunlit Man chapter 8#
  10. The Sunlit Man chapter 13#
  11. a b The Sunlit Man chapter 11#
  12. The Sunlit Man chapter 19#
  13. The Sunlit Man chapter 33#
  14. a b The Sunlit Man chapter 36#
  15. The Sunlit Man chapter 37#
  16. a b The Sunlit Man chapter 47#
  17. The Sunlit Man chapter 22#
  18. a b c The Sunlit Man chapter 50#
  19. The Sunlit Man chapter 1#
  20. The Sunlit Man chapter 25#
  21. Dragonsteel 2023
    Arcanum - 2023-11-21#
  22. The Sunlit Man chapter 4#
  23. The Sunlit Man chapter 29#
  24. a b The Sunlit Man chapter 42#
  25. The Sunlit Man chapter 48#
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