Mereoleona Vermillion 「メレオレオナ・ヴァーミリオン Mereoreona Vāmirion」 is a noblewoman and the first daughter of the Clover Kingdom's House Vermillion, one of its royal families. She is also the temporary captain of the Crimson Lion squad and the Royal Knights squad.
Mereoleona is a woman with blue eyes and long, wavy vermilion colored hair. Like her brothers, she has red markings around her eyes, and like Leopold, she has one sharp, pronounced canine tooth.
Mereoleona's attire consists of a white tunic, covered by a long, dark blue shirt with long sleeves and high collar. The shirt is decorated with fabric with vertical stripes design on its edges and collar and along the sleeves, which she keeps rolled up to her elbows. In order to keep the shirt together, she wears a purple sash around her waist. She wears white trousers. On top of her attire, she wears a long red cape.
As a member of the Crimson Lion squad, Mereoleona wears the squad's signature robe that only covers her torso. The robe has intricate designs at the lower front edge and is complemented with a scarf. A pair of ropes are protruding from between the scarf and the robe at the front and a stone is decorating each end. Lastly, the squad's insignia is located at the center back of the robe.
Six months after the elves' attack, Mereoleona has cut her hair short.
Mereoleona has a hostile attitude and short temper. She is a loud and aggressive woman who believes actions show more than words. However, despite this, Mereoleona shows a deep understanding in how to motivate others, even those she just met. She respects anyone who is willing to get strong and does not judge others based off their upbringings or lineage.
She dislikes the Royal Capital so she spends most of the year out in the wilderness, hunting wild animals and basking in natural mana. Despite her dislike and initial refusal for the captaincy, she takes over when Fuegoleon Vermillion is incapacitated, and leads the Royal Knights in an attack on the Eye of the Midnight Sun, hoping to avenge her brother.
She is also shown to have a lack of modesty or natural view of nudity, as she did not hesitate to order everyone (both men and women) to strip down and bathe together in the hot spring, and smile at the men's "enthusiasm" when she heard them trying to peek at the women.
Mereoleona was born as the first daughter of House Vermillion. She is trained by Acier Silva, whom she is never able to defeat, despite her strength and elemental advantage.
The day before she would receive her grimoire, Mereoleona and her younger brother, Fuegoleon, have a fight after she disparages the Magic Knights. The resulting blaze destroys part of the Vermillion Estate, and the confrontation becomes known as "Hot-Blooded Tuesday".
Years later, Mereoleona refuses the captaincy of the Crimson Lion squad, allowing Fuegoleon to become captain.
After the assassination attempt on Fuegoleon and his subsequent coma, Mereoleona takes over as captain and, at Julius Novachrono's request, attends the annual Star Awards Festival.
After the Crimson Lions place fifth, Mereoleona berates them for letting Fuegoleon down and decides that they should all further train in hot springs. When she hears Asta exclaim about the idea of the training camp, she grabs him with a paw of fire and invites him to come along. Yuno goes to leave, but she grabs him, too, since she wants to see the power of the two best rookies.
As Yami Sukehiro is praising himself, Mereoleona shows up and Yami laughs at Asta being caught, before she grabs him as well for training. She goes on to grab Charlotte Roselei and Noelle Silva and carries them all off to the Ultime-Volcano Mountain Trail. She encourages them to reach the summit and the hot spring there, but none of them are excited. She then kicks Asta and Leopold onto the trail because they are distracted.
When Noelle begins to doubt herself, Mereoleona notes how the girl has changed and challenges her to be like her mother, which motivates her. When Asta collapses from exhaustion, Mereoleona tells him to go home as he lacks the magic and the determination to climb the mountain, and speculates that luck let Asta reach the second place rookie and could let him become Magic Emperor. However, Asta disagrees and is motivated to continue. However, he struggles to come up with an answer and makes a joke of it, which incites Mereoleona to threaten sending him home. She then leaves him to struggle.
After Asta accesses his Anti Magic and loses control of the transformation, he shoots straight to the top of the volcano, where Mereoleona is waiting for him. She releases her mana and jumps at him while he warns her to run away. Pointing out that lionesses are the hunters of their prides, she leaps midair to Asta's left and punches him, sending him crashing into a rock. She compliments him for improving and then demands that he strip to enter the hot springs.
After everyone reaches the summit, Mereoleona sends back those who did not arrive before sunset, and invites the rest to soak in the hot springs. Sol Marron divides the pool, and the women all undress and enter one side. Mereoleona drinks sake as she soaks and offers some to Charlotte, who refuses, which Mereoleona finds insulting. Charlotte then faints after thinking about Yami naked, leaving Mereoleona confused. Mereoleona notices Noelle and is reminded of Noelle's mother, Acier. She compares the two, highlighting Acier's strengths that are Noelle's weaknesses, but points out that Noelle will surpass her mother with her own strength.
Several days after the Royal Knights Selection Exam, Mereoleona barges into the Black Bulls' base. She presents Yami with a gift of alcohol and then carries off Asta, Noelle, and Luck Voltia. In the Royal Capital, Mereoleona addresses the assembled Magic Knights and announces that they are the Royal Knights squad and she is their captain. After counting heads, she realizes someone is missing. As Zora Ideale drops in late, Mereoleona attacks him, but he counters it, which impresses her.
After yelling at the distracted Black Bulls, Mereoleona orders everyone to change into their new robes. She then introduces three additional Knights who were chosen: Siren Tium, Cob Portaport, and Nozel Silva. She questions Nozel's decision to join, but King Augustus Kira Clover XIII explains that a royal captain is needed for the Royal Knights. Mereoleona then announces that the Eye of the Midnight Sun's hideout is the dungeon in the Gravito Rock Zone.
After gathering the squad beneath the dungeon, Mereoleona explains the layout and divides the squad into five teams, choosing Asta and Zora for herself. Zora tosses a rainbow stink bug at her, but she catches it and smashes into his face. When Zora questions why she would take two commoners, she explains that she respects strength, not social status. She then tells the teams to head for the center room and to use whatever means or magic they wish.
As her team enters the dungeon, they are confronted by three mages, and seeking revenge for her brother, Mereoleona incinerates them with her flaming aura as she dashes past them and declares that she will defeat Licht. As the group makes their way deeper, Rhya joins the group disguised as Asta, so Mereoleona burns both of them. Rhya drops his disguise and confronts Mereoleona; however, she quickly smashes through his Dark Cloaked Avidya Slash and punches him directly.
Rhya is forced to keep retreating and attacking from long-range, but Mereoleona repeatedly smashes through the spells and closes the distances. Without hesitating, Mereoleona punches Rhya's copy of the Demon-Slayer Sword and then unleashes a Calidus Brachium Barrage, using Mana Zone to hit from every angle. She continues the barrage as Rhya falls back. Unable to escape, Rhya activates his self-destructive magic, but Asta nullifies it before Mereoleona's strikes could set it off. After Asta punches Rhya and demands to hear his story, Mereoleona grabs the boy and threatens him for intruding. She declares that the Eye of the Midnight Sun must be crushed, but Asta counters that they should strive for a world of understanding each other, which impresses Mereoleona with the audacity.
Suddenly Rhya begins glowing and stands back up, with his injuries healed. He attacks with both Light and Dark Magic spells, and Mereoleona is forced to defend herself and a surprised Asta. Mereoleona remarks that this proof against peaceful coexistence, but Asta counters that he will find a new path. Mereoleona tries to capture Rhya in another Calidus Brachium Barrage, but he dodges the punches and attacks back with Spatial and Light Magic. One of the attacks manages to graze Mereoleona's shoulder. The fight is interrupted when Lira falls through the ceiling atop his Four-Headed Lindworm.
Mereoleona questions if their comrades have been turned into other people. Lira attacks with the Lindworm, and Mereoleona counters two of the magic blasts. After Asta's Anti Magic fails to free Rill and more possessed Royal Knights appear, Zora and Asta agree to retreat, so Mereoleona smashes a hole in the wall, throws Asta and Zora through it, and collapses the wall to cover the hole. She then counters Rhya's and Rill's spells before challenging the five elves by herself.
The five elves coordinate to attack in series. Their combined Angel Flapping proves too numerous for Mereoleona to counter. Lira paints a giant that is too large for Mereoleona to burn away, and when she tries to dodge the punch, Rhya warps the fist to a different angle and Miniature Garden of Illusory Snow dulls Mereoleona's reactions, enabling the punch to connect and knock her down. Rossa tries to trap her in a sandstone prison, which infuriates Mereoleona. While she is distracted, Rhya ambushes and slashes her while the other elves rain more feathers down on her. She survives and fires a punch at Rhya. Mereoleona keeps fighting but after taking more injuries, she decides to unleash Calidus Brachium Purgatory, which engulfs the entire room in fire. The elves use up most of their magic to defend, and Mereoleona is also exhausted but remains standing. The elves combine their remaining magic into a final spell, but Asta and Zora return and defend Mereoleona, reflecting the spell back at the elves. Although the spell misses, Asta and Zora grab the unconscious captain and run. Rhya chases them, and Asta throws Mereoleona over to Zora and is taken.
After escaping the dungeon, Zora and Mereoleona regroup with the remaining Royal Knights. Mereoleona rests against a tree, and Nozel uses Eilia's Booth on her and the other injured. Nozel receives a distress call from his squad, so he creates a vessel to convey the Royal Knights all back to the country. As they reach the edge of the kingdom, Mereoleona's injuries are healed but she remains unconscious. Along the way to the capital, Nozel drops Mereoleona off so she can finish resting.
As soon as she wakes up, Mereoleona rushes to Clover Castle and, alongside her awoken brother, swiftly defeats the elves attacking the Black Bulls. Before the gate to the Shadow Palace closes, Mereoleona goes with Fuegoleon and Mimosa Vermillion, while Nozel carries Asta and Noelle and while the Black Bulls and Kirsch Vermillion fight off more possessed Golden Dawns.
Once they pass through the gate, the group is separated and scattered to different parts of the palace, and Mereoleona encounters Vetto and they fight, evenly exchanging blows and enjoying the fight. She drops her guard, letting Vetto punch her jaw, so that she can charge a counterattack. She punches Vetto in the jaw, knocking him unconscious, and then leaves him lying on the floor.
Mereoleona later reunites with some of the other Magic Knights in the Shadow Palace. She attempts to push back the devil's magic that is flooding down from the topmost chamber, but her magic has no effect. When Licht and Lemiel Silvamillion Clover send out protective auras to the elves, Nozel pulls Mereoleona and Jack to safety in the light. Fana leads the group up toward the topmost chamber and the exit, and when the protective light disappears, Valtos saves the Magic Knights and elves and warps them up to the topmost chamber.
The humans and elves return to Clover Castle, and Mereoleona wishes to fight the still rampaging elves. Mereoleona then watches as William Vangeance, Licht, and Asta work together to dispel the Reincarnation Magic and exorcise the elf spirits.
Since her magic proved useless against Zagred's magic, Mereoleona returns to training in the Ultime-Volcano Mountain.
Six months later, after Yami and William are kidnapped by the Spade Kingdom, Nacht Faust invites her to join the mission to rescue the two captains. Mereoleona agrees to go but is more interested in fighting the ones who captured them.
Mereoleona is stationed in the capital of the Spade Kingdom in preparation for the invasion. When Zenon Zogratis unleashes a giant demon on the castle town, Mereoleona comes to the Resistance's aid and punches the demon. The punch is not enough to defeat the demon, so Mereoleona assimilates a large amount of Fire Magic into her body, which greatly enhances her strength. After blocking the demon's attacks and knocking it onto its back, Mereoleona unleashes Calidus Brachium Purgatory: Abyss, pummeling the demon into the ground and engulfing it in flames. She is gloating over the demon when the roots of the Tree of Qliphoth burst forth from the castle. As a horde of low-ranking devils bursts from the castle, she recognizes the feeling of their magic power. The demon stands back up and forms a pair of wings, which excites Mereoleona, who is looking forward to the challenge.
As the fight continues, her Hellfire Incarnate spell grows in power, and she eventually overpowers the demon and destroys its head and shoulders, killing it. She then flies over to face the devils pouring out of the castle. However, when the second gate to the underworld opens, Lucifero absorbs the devils into a giant monstrous body. Although Lucifero's Gravity Magic presses the Spirit Guardians and Resistance members to the ground, Mereoleona remains standing. She and Fuegoleon then combine their magic to stop one of Lucifero's tentacles from crushing the Resistance members.
After Asta slices the monster and destroys the Qliphoth Advent Ritual, Mereoleona and most of the other captains meet up and relax over their victory. However, Lucifero compresses the monster's remains into a body, through which he manifests in a half-complete form. He then forces the humans to prostrate themselves before him. Asta attempts to fight Lucifero, but once Asta is sent crashing into the ground, the captains rally around him and prepare to fight Lucifero. Mereoleona and Jack simultaneously unleash barrages but Lucifero blocks all of the attacks. He catches Mereoleona's punch and crushes the bones in her left forearm before punching her away. Despite her injuries, Mereoleona refuses to give up and attacks again, and Lucifero knocks her back again. Asta manages to cut off the tip of one of Lucifero's horns, which infuriates the devil. Mereoleona punches Lucifero to distract him while Dorothy and Charlotte pull away the injured Asta. As the captains pass along the Black Bull, keeping him away from the devil, Lucifero punches Mereoleona, sending her flying, but Dorothy's magic catches her. When Nozel's Mercury Magic temporarily restrains Lucifero, then Mereoleona, Fuegoleon, and Salamander blast him with their combined magic power. However, Lucifero emerges unscathed, knocks Mereoleona aside, and throws Fuegoleon into Rill, knocking out both captains and breaking Twilight of Valhalla.
Fire Magic: Mereoleona uses this magic attribute to generate and manipulate the element of fire. She usually shapes the fire into a lion's paw.
Calidus Brachium Purgatory: Abyss
Reinforcement Magic: Mereoleona uses this form of magic to increase her physical abilities. Her skill is great enough to protect her from being burned while bathing in lava.
Master Hand-to-Hand Combatant: Mereoleona is extremely skilled in hand-to-hand combat, easily able to overpower any opponent she encounters. Zora Ideale notes that she is more of a fighter than a mage. She employs it as her main style of fighting, and also uses her magic in conjunction with her hand-to-hand prowess for more deadly strikes.
Immense Strength: Mereoleona possesses tremendous physical strength, as shown when she sends Asta flying into a rock with a single punch despite him being in his Black Asta form. Her physical strength is great enough to fight on par with Vetto. While using Hellfire Incarnate, she is strong enough to knock aside the arms of a giant demon and push the demon onto its back.
Immense Speed: Mereoleona possesses tremendous raw speed, as shown when she outmaneuvers Asta in midair while he is in his Black Asta form. She is so fast that she is able to parry Rhya's spells with great ease, with him stating that her reactions are on par with Vetto. Zora states that her speed is monstrous.
Immense Endurance: Mereoleona possesses extraordinary endurance, as shown when she takes the combined assault from five elves with no signs of being in pain and continues to fight. Even after using up all her mana to use her ultimate attack, she remains standing and wanting to continue fighting.
Enhanced Mana Sensory: Mereoleona is extremely skilled in sensing mana, as shown when she instantly realizes that Rhya cannot copy Asta's Anti Magic and punches straight through his copy of the Demon-Slayer Sword with no hesitation.
Immense Magic Power: As a royal and captain of a Magic Knights squad, Mereoleona possesses an immense amount of magic power. Her magic power is so massive that Rhya states that it is not just from her being a royal, but because it is a completely unknown human strength. According to Vetto, Mereoleona is probably the strongest human in the Clover Kingdom.
Mana Zone: Mereoleona can control all the mana in an area around her to increase her spells' power and range, to predict opponents' attacks, and to maneuver in mid-air.
Grimoire: Mereoleona possesses a three-leaf clover grimoire that contains various fire-based magic spells.
Mereoleona cares about her younger brother, Fuegoleon, despite their conflicting views on Magic Knights and training. When Fuegoleon is incapacitated, she steps out of her comfort zone and replaces him as captain in order to seek revenge. She also thinks highly of his abilities and power, rating him as the strongest.
Mereoleona is very rough with Leopold and will physically harm him if he talks back to her or argues. She believes he is weak without Fuegoleon so she forces him to train at the hot springs in order to get stronger.
Mereoleona has known Noelle ever since she was a little girl. She cares deeply for Noelle and respects her a lot for becoming a stronger woman despite her inability to control her magic and being deemed a failure by her own family. Mereoleona never insults Noelle and sees her mother inside her. She encourages Noelle to continue to get strong like her mother and motivates her when she begins doubting herself.
Mereoleona was very close to Acier and was trained by her. She was never able to beat her despite being extremely powerful and possessing the elemental advantages over her own Steel Magic; due to this Mereoleona admired her a lot. After she died, Mereoleona often refers to her when talking to Noelle and uses her as motivation for her to get stronger.
Mereoleona is very interested in Asta after seeing him place as a top rookie during the star awards. At first, she thinks he only got that far due to luck and berates him for having no magic. After Asta proves her wrong and climbs the volcano, Mereoleona realizes he is not all talk or made it as far as he did due to luck. During their invasion on the Eye of the Midnight Sun's base, Mereoleona takes Asta with her personally due to her interest in him. When facing the five elves, she throws Asta away so he can escape while she fights the others. She is also willing to fight Lucifero herself in order to protect Asta because she looks forward to Asta's future as her "prey."
Mereoleona and Yami Sukehiro argue easily and he even goes as far as calling her "Anegoleon" 「アネゴレオン, Viz: "Sisgoleon"」, which annoys her. Despite their clashes, they both have great respect for each other and admire each other's strengths. She personally visits the Black Bulls base to deliver a gift to Yami as thanks for visiting her brother, Fuegoleon, in the infirmary.