Krolia is a female Galra and the mother of Keith, as well as a spy for the Blade of Marmora. Kolivan gave Keith the mission of infiltrating the base where she was located, extracting her, and destroying the weapon housed in the base.
Despite being Galran, Krolia bears a striking resemblance to her son, Keith. Krolia has light purple, lavender skin, prevalent in all Galra. Her hair is a darker shade of purple, and has a pale magenta shade around the back of her hair. She has a darker purple stripe on her neck that curves around her face, giving it the appearance of having two stripes that reach up to under her eyes. Unlike most Galrans, her eyes have violet irises. She was quite fit, and was able to return to peak physical conditioning not long after giving birth, a feat not easily achieved by most human women.
Krolia is known to have been a member of the Blade of Marmora for an indeterminate amount of time prior to arriving on Earth. Following Sendak's acquisition of the Red Lion, the Galra Empire managed to engineer a tracker that could locate Voltron Lion signatures at close range. As Zarkon sent out thousands of scouts equipped with the tracking method, Krolia was sent to Earth as a spy in one of the scouting parties by the leaders of the Blade of Marmora. Knowing that she could not afford to let the Lion fall into Zarkon's hands, Krolia shot down most of her fellow pilots in an effort to sabotage their theft. After taking a critical hit, Krolia crash landed not far from where a southern man with black hair would find her, carving his way into her ship with an ax and presumably nursing her back to proper health again.
Over time, she considered her crashing on Earth to have been the best thing to ever happen to her. After falling in love with the man who rescued her, Krolia decided to protect the newly rediscovered Blue Lion, and her lover agreed to help her in this chosen duty of hers. Not long after, they conceived a child, whom they named Keith. But trouble soon came in the form of more Galra scouting parties. After nearly losing her mate in the process of protecting Blue, Krolia decided it would be better for her child and lover for her to return to the Empire and lie about the location of the lion. Kissing her son goodbye and bequeathing her sword to her lover, Krolia left Earth, intent on protecting it from the Galra, hindering their discovery of the Blue Lion for the next eighteen years.
By present day, Krolia managed to embed herself under the command of Warlord Ranveig. When Ranveig discovered an unmarked transport traveling through his territory, Krolia investigated the wreck on his behalf, finding only a single container of quintessence, discovered to be more potent than any quintessence the Galra had obtained. In an effort to track the pure quintessence to its source, Krolia did a radiation scan of the ship and determined that it had passed through the Quantum Abyss.
Following Ranveig's departure, Krolia minded his base where he had experimented with the quintessence that resulted in a heavily mutated and vicious monster. Rumor of the new superweapon soon reached the ears of Commanders Ladnok and Trugg, who began fighting over Krolia's planet for control of the superweapon. At the same time, the Blades sent an agent to make contact with Krolia, whom she discovered to be a grown-up Keith. Upon meeting, Krolia did not reveal her identity as his mother and instead cut straight to business as they attempted to access the superweapon. Unfortunately, Trugg managed to breach the base and her troops overpowered Keith. Refusing to abandon her son again, Krolia bargained with Trugg for their freedom in exchange for the access codes to the superweapon vault, as without the codes the vault would self-destruct. Trugg did provide them a ship only to fire on the two Blades once she had the codes. While Keith piloted them to the safety, he berated her for giving the superweapon to Trugg, but she confidently stated that it was the other way around.
Once they had reached safety, Keith inquired how she was able to awaken his Marmora blade. It was then that Krolia revealed her identity as his mother. Naturally, he bombarded her with questions as to how she met his father but she brushed them aside, insisting they travel to the Quantum Abyss, suspecting the quintessence Ranveig found was connected to the same quintessence Keith and Kolivan were tracking.
Upon arriving at the outer edge of the Quantum Abyss, their ship was attached and destroyed by native space creatures, forcing them to continue on foot. During this time, they experienced periodic flashes from the center of the Abyss which showed them visions of the past and future; Krolia explains that it was an example of time collapsing near the dark stars. For Keith, he learned how his parents met and why Krolia had to leave. He assumed that it was because she had to put the mission first, only for her to correct that she wanted to protect her son.
They hitch a ride on the back of a whale-like creature, which possessed a habitable surface which they built a home for two years of the warped time in the Quantum Abyss. During that time, Krolia experienced a vision of Keith's father's passing, saddening her. Additionally, mother and son adopt a Cosmic Wolf that crash-landed on the creature.
Eventually, they arrive on a planet beyond the Quantum Abyss, where they discover a domed facility, where inside, they met an Altean named Romelle, whom they learned was part of a hidden colony of Alteans Lotor rescued. Romelle told them that Lotor had set up a supposed second colony which many Alteans that were selected to travel there had never returned from until her brother Bandor managed to warn her with his dying breath that it was all a lie. Keith suspected that the colony had to be nearby if Bandor had managed to return to his sister in a weakened state. Krolia suggested the colony was on orbiting moon, which they flew to in an old Altean pod. There, they discover the second colony was in fact a laboratory which Lotor was using to harvest quintessence from Alteans.
Krolia is a woman of great loyalty, discipline, and principles, as she managed to complete her mission to destroy the Galran superweapon without compromising her son's safety while simultaneously double-crossing her enemies in order to satisfy her own agenda and orders.
Due to her duty as a Blade, Krolia has had to endure great internal conflict. While she did leave Keith on Earth with his father, Krolia did feel immense regret for having to abandon her son, determined to not do so again when she betrayed her enemies in order to protect Keith, showing that she does indeed love her son immensely. Her affection for Keith's father prompted her to leave her luxite sword with her former lover, effectively leaving Keith with the only evidence of his heritage. She deeply loved her mate, appearing devastated when she believed him to have been killed by the Galra. This was also evident in her apparent horror from a vision in the Quantum Abyss of her son standing before his father's grave on Earth as a young boy. She eventually left for the sake of protecting the thing she loved most in life: her son.
Krolia and Keith both appeared to have come to terms with her decision to leave for Keith's safety during their two years living on a cosmic whale's back in the Quantum abyss. During those two years, they spent their time hunting for food together, training a cosmic wolf, and finally getting a chance to be a family.
She also possesses a cunning streak. She purposely allowed Commander Trug access to the super weapon, knowing that it was a living entity that would murder the unsuspecting commander and her forces, thus playing her for a very dead fool. This shows that while Krolia may be similar to her son in her inability to separate her emotions from her mission, she does take more calculated risks to compensate for her somewhat impulsive behavior.
As a spy for the Blade of Marmora, Krolia was a profoundly skilled actress, able to lie to the Empire about the location of the Blue Lion, preventing their discovery of it for the better part of twenty years.
Due to her time as a Blade, Krolia is a highly capable melee combatant, able to take on several highly trained drones and Galra soldiers. She is notably skilled with her luxite blade, showing herself to be a master with both a knife and sword. Her skill with edged weapons put her on par with master sword fighters like Antok, Kolivan, and Lotor, as well as naturally gifted sword fighters such as Keith and Lance.
However, as she was not invincible, Krolia was skilled at manipulating her enemies into harming themselves, sometimes with lethal results in the case of Commander Trug, as the commander had no idea that the super weapon she sought was a living creature with a savage need to kill.
- The name "Yurak" that Krolia wanted to name Keith is a reference to Yurak of Defender of the Universe.