Catherine Ashdown was a Shadowhunter.
In 2000, Catherine was tasked with escorting the orphaned Jonathan Wayland to the New York Institute. They traveled to New York from Idris through ship. During the trip, the boy asked her about the Lightwoods and she guessed that he was afraid that they would be unkind to him. When Jonathan observed that there were many werewolves on the ship, she griped about how annoying children raised in Idris — referring to Jonathan — were and sent him to bed.
When a fight broke out on the deck, between the werewolves and a new group of Shadowhunters and vampires, Catherine left her quarters and ran into the path of an attacking werewolf. Her throat was ripped out by the werewolf, saving Lily Chen in the process but killing her. Lily later recognized her and pointed her out to Raphael, and Brother Zachariah paid his respects to her before closing her corpse's eyes.
- Son of the Dawn (first and only appearance)