Servant AUX Voroid "K6-X4" (サーヴァントＡＵＸヴォロイド“Ｋ６－Ｘ４”, Sāvanto AUX Voroido K6-X4?), also called Dark Knight-Kun (黒騎士くん, Kurokishi-kun?), is the partner of Mysterious Heroine X Alter in the Servant Universe.
Profile
Background
Officially designated as Servant AUX Voroid "K6-X4", K6-X4 is a "Servant auxiliary high-performance robot" that was designed for combat and navigation assistance. His body was created from a repurposed head of a rampaging mechanical giant that once turned an entire planet into scorched earth. He became X Alter's trusted partner, and she gave him the nickname of "Dark Knight-kun".
Appearance
K6-X4's body is reminiscent of an ancient helm. He has minute Alternium crystals buried with in his head that are synchronized with X Alter.
Personality
He has a mean personality and a harsh tongue, described as being unfit to appear in public. He looks down on humans and ignores their orders as a matter of course, only loyal towards X Alter alone.
Role
Fate/Grand Order
Mysterious Heroine X (Alter) Trial Quest
The Alterium shard n K6-X4's head receives mana waves leaking through the cracks of multidimensional space. By sheer coincidence, K6-X4's wavelength matches that of Ritsuka. Ritsuka's mind is thereby transferred into the robot, allowing them to experience X Alter's life. X Alter eventually deduces the problem and removes the Alterium shard from his head, thereby returning Ritsuka's mind to their world.
Abilities
Development