In 2007, Brother Jeremiah was called upon by Hodge Starkweather to assist them in retrieving Clary's seemingly lost memories. He realized that a magical block had been placed in her mind to repress her memories, and since he could not break the block on his own, he took her to the Silent City so he could receive help from his fellow Silent Brothers. Once they all looked into Clary's mind, they discovered that Magnus Bane had put the block on Clary's memories. Unable to help her further, Brother Jeremiah led Jace and Clary out of the Silent City.
Valentine Morgenstern sent Agramon, the Demon of Fear, to the Silent City in order to use him to incapacitate the Silent Brothers, which allowed him to steal the Mortal Sword kept there. Brother Jeremiah was among the many Silent Brothers killed in the procress, after he was literally scared to death by the powerful Greater Demon.
Just before his death, Brother Jeremiah managed to make his way to the holding cell where Jace Herondale was held for the evening. He then dropped to the floor and died in front of Jace's cell, minutes after Jace had heard the screams from upstairs after the Silent City was invaded.
Brother Jeremiah had pale white skin, littered with runes, some of which were the most powerful runes in the Gray Book. His head was shaved and was said to look like an egg. He had no eyes, only indentations where they should be. His mouth was sewn shut, due to the fact that he no longer needed to speak, thanks to the powerful runes placed on him as a Silent Brother that allowed him to communicate through his mind.
He was described to have smelled like "spices."
Skills and abilities
As a Shadowhunter, particularly Silent Brother, Brother Jeremiah possessed an array of powers, including:
- Telepathy - Brother Jeremiah possessed the ability to read the minds of those around him.
- Runes - As a Shadowhunter, Brother Jeremiah had the ability to bear the marks of the angels which granted him superior strength and many other abilities. Being a Silent Brother also allowed him to possess strange and more powerful runes interpreted from the Gray Book exclusive only to the Brothers, being those who have chosen to dedicate their lives to the research of their magic.
- Stele - Brother Jeremiah, like any other Shadowhunter, also owned a stele, which he used to draw runes.