Sister Cleophas is an Iron Sister, particularly a Maker who shapes the adamas for the others to carve. Before she became an Iron Sister, she was a Shadowhunter and the mother of Amatis and Lucian Graymark.
For reasons unknown, she decided to leave her family when her son, Lucian, was still very young, leaving her eldest, Amatis, to raise him. Since then, she was never seen again by her children.
Sister Cleophas was the one to greet Jocelyn Fray and Isabelle Lightwood when they came to the Adamant Citadel in 2007. Unable to make sense of Magnus Bane's notes on Sebastian Morgenstern and Jace Herondale's disappearance, so she passed them onto Sister Dolores, who did. When the Sisters realized that no earthly weapon would be able to separate Jonathan and Jace, she made it clear that even if they knew of Heavenly or demonic weapons that could help, the Law would prevent them from sharing the information. When Isabelle accused them of being heartless, Cleophas merely reminded her of their motto, "fire tests gold". Seeing Isabelle storm out, she told Jocelyn that Isabelle would make an excellent Iron Sister and to let them know if she was ever interested.
When Jonathan and his Endarkened forces attacked the Citadel, Cleophas first remained inside, to protect the interior armory, or destroy it if ever the enemies get through the gates. When the heavenly fire within Jace was released by Jonathan in battle, the Sisters temporarily abandoned the armory to come to Jace's aid. Later, when Brother Zachariah was burned by the heavenly fire, Cleophas was among the Sisters who fretted over him.
Cleophas is a tall woman who, like other Iron Sisters, has an almost ageless face, seemingly both unlined yet ancient. On her face, is an intricately curlicued tattooed mask encircling her orange eyes. She has long, dark black hair that she wears in thick braids. Her fingers seem to have been stretched to an unnatural length. Her nails are filed to a point and tipped with electrum. She wears a long, loose white gown, bound tightly at the wrists and under her breasts with silver-white cord, demon wire, in tradition with the Iron Sisters.