Horace Dearborn is a Shadowhunter. He is a member of the Cohort, and he suggested to the Clave that all Downworlders should be registered. For this desired reform, he and other members hold rallies for its passage.
When his daughter Zara was young, Horace's wife was killed and he was left to raise Zara to share his hateful views on Downworlders. After the Cold Peace was established, Horace gathered a group of radical Shadowhunters who shared his views and became a member of the Cohort, establishing himself as the unofficial leader.
In 2012, Horace kept track of his daughter's progress at the Los Angeles Institute by trading letters with her. He later attended the Council meeting where Annabel Blackthorn was to testify and spoke out against her and the Blackthorns, taking part in the heckling of Annabel by the Cohort members.
Horace is a very ambitious and conniving man. He hates Downworlders and any who associate with them, including Shadowhunters like Mark Blackthorn who have Downworlder blood.
Horace is a brown-haired man with an expressionless face.
- Lord of Shadows (first appearance)