Keratrix is a minor character in The Defenders of Shannara trilogy. He is a young Druid who replaces Sebec as the personal assistant to the Ard Rhys Aphenglow Elessedil. He later becomes Isaturin's assistant when Isaturin succeeds Aphenglow as Ard Rhys.
Keratrix is one of the few Druids who know in advance that Aphenglow is about to die, and says goodbye to her before she boards an airship to travel to the Hadeshorn and pass away.
A few years later, Keratrix is killed when the sorcerer Arcannen, who entered Paranor disguised as Isaturin, uses Keratrix to gain access to the chamber where the Druids' most important artifacts of magic are kept. When Arcannen's eagerness and obvious desire for the crimson Elfstones makes Keratrix suspicious, the young Druid attempts to leave and get help, but Arcannen stops him and breaks his neck. The sorcerer raids parts of the chamber and leaves in a rush.
Keratrix's body is found a short while later by Paxon Leah, the Blade of the Ard Rhys, and the Druids Miriya and Oost Mondara. Miriya, Paxon, and Oost race to where the Druid airships are kept to find Arcannen, still in the form of Isaturin, boarding one of the ships. Upon seeing Paxon and Miriya, the false Ard Rhys halts their advance with a wall of magic fire and flees in the ship. Paxon and Miriya follow closely after him, with Miriya using her magic to keep track of the sorcerer. The pair tracks Arcannen all the way to the ruins of Kern, where Arcannen sets down his airship and makes his stand. He is killed by Miriya and Paxon.
Keratrix is small and slight and reminds Paxon Leah of Sebec, who was Paxon's closest friend when he first arrived at Paranor.