Cain was from the White Fang Mountains and descended from the local freefolk. He was found by Duke Perrington and was his candidate in the King's Champion Tournament. Cain murdered several of his rivals by calling on the Ridderak using Wyrdmarks. As a result, Cain gained the strength of his opponents and magical powers, which helped him during the Tournament. In the final round, he almost defeated Celaena Sardothien, but with Elena's help, she triumphed over him. Cain then attempted to murder her, but Chaol saw what he was doing and killed him to defend Celaena.
A denizen of the White Fang Mountains, Cain was a skilled warrior. To add on to this, he displayed blatant ambition and bloodlust, willing to harm or kill any who stood in his way. It is unknown if these malicious traits were his true personality or just amplified by the Valg who possessed him.
Cain was an extremely huge, bulky man with dark hair. During the King's tournament, his size and power increased, effects of his use of Wyrdmarks and the Valg's ability to consume his victims' power. He also wore a black Wyrdstone ring, inducing the Valg to live inside him.
- Throne of Glass (first appearance)
- Crown of Midnight (mentioned only)
- Heir of Fire (mentioned only)
- Queen of Shadows (mentioned only)
- Tower of Dawn (mentioned only)
- Kingdom of Ash (mentioned only)
- Cain may have been a shaman of the Wild Tribes, which explains how he was able to use Wyrdmarks.