Katja is a petite and slender young girl. She has short dark blue hair and light brown eyes. Katja wears a bluish-white sleeveless dress connected to a light blue choker worn around her neck, blue sandals, and palish blue armbands. Doranbolt states that she bears a strong resemblance to Wendy Marvell.
Katja is a kind-hearted and quiet person, usually very calm and polite. In addition, she is also quite sensitive, slapping Doranbolt when she mistakenly thought he was looking at her chest. She often displays a sad expression on her face, due to having witnessed several friends perish in the past; this experience has caused her to give up on her life.
Katja is a descendant of one of Will Neville's disciples and she has been trained to utilize Celestial Spirit Magic. During her lifetime, she inherited the Organic Link to thwart the completion of the Infinity Clock.
Key of the Starry Sky arc
Note: Events occurring in this arc are only in the anime and do not constitute canon material.
Katja is seen carrying Nico in front of a tree and wonders about how long the tree would continue to live. A man is then seen running up and warns Katja not to wander off, and she tells Nico to escape if it is frightened.
She is later seen inside a cathedral when Lahar and Doranbolt come to visit her. She and Doranbolt have a talk regarding a girl who 'died' seven years ago who appeared to be Wendy Marvell. Later, she summons Caelum and Doranbolt is amazed because she can summon two spirits at the same time. However, their small talk is cut short by Racer, who states his mission to destroy the vessel.
She is later seen running with Lahar on a hill. Just then, Racer and Doranbolt arrive, with the latter telling her to run. She is later saved by Doranbolt who manages to intercept the stab from the red knife wielded by Racer. However the link markings on her body disappear and she loses her ability to perform Celestial Spirit Magic. She later tells Doranbolt to live a new life and forget about the past.
Alvarez Empire Arc
Note: Events in this arc occur only in the anime and do not constitute canon material.
Former Magic and Abilities
Celestial Spirit Magic (星霊魔法 Seirei Mahō): Katja is a former practitioner of Celestial Spirit Magic, allowing her to summon Celestial Spirits, creatures with Magic Power that reside in the Celestial Spirit World, for combat.
- Multiple Summoning: She was capable of summoning two Silver Key spirits and maintain their power simultaneously with relative ease.
- Gate of the Canis Minor Key: Summons the Canis Minor, Nikora. (former)
- Gate of the Chisel Key: Summons the Chisel, Caelum. (former)