|“||There's a hierarchy of command, and the Inquisitor is near the top.||”|
The Inquisitor investigates Nephilim for the Clave, making sure that they have not broken the Covenant or the Accords. The Inquisitor typically serves as the prosecuting attorney on Shadowhunter trials, and is thus, along with the Silent Brothers, legally permitted to use the Mortal Sword on Shadowhunters to compel the truth out of them. The Inquisitor may also choose to recommend or request the punishment or sentence in some cases, though these also require the approval of the Council; such was the case when Inquisitor Herondale exiled the Lightwoods and enforced Hodge Starkweather's curse.
According to Isabelle, if there was a hierarchy in command, the Inquisitor would be near the top, as shown when Inquisitor Herondale sent Jace to the cells underneath the Silent City just for talking back to her.
- Victor Whitelaw (as of 1878)
- Imogen Herondale (until September 2007)
- Aldertree (briefly, in September 2007)
- Robert Lightwood (December 2007–current)
- According to Jace Herondale, most of the Inquisitors appointed were corrupt.
- The Inquisitor wears gray robes when appearing in events or the like in an official capacity, or when attending to his duties so as to distinguish himself/oneself and the position he/she holds.