Changes

Rio has dark pink eyes and like [[Reginald Kastle|her brother]], she has pale skin and dark blue hair with light blue bangs. Rio also wears a ring on her right little finger, which was previously owned by her brother. Rio's appearance attracts many initial admirers, including [[Bronk Stone|Bronk]].

Her attire includes a white jacket over a light pink shirt (her skirt is also longer, covering her legs in the dub), black stockings, white skirt and shoes. The left coattail of her jacket has a conch-like ornament hanging down. At [[Heartland Academy|school]], she wears the standard uniform, with hers being green due to her status as a second year student (in the dub, her skirt is lengthened). She wears longer stockings than most female students. Her casual outfit is composed of a blue-white striped sleeveless T-shirt, a blue upper knee length skirt and white high-heeled sandals.

===Personality===

Despite her appearance and previously spending a large amount of time in hospital, she is a confident and adamant person, getting annoyed when things do not go her way. This is usually shown when conversing with her brother. Her confident personality assists in her interests which allows her to conquer sports such as soccer, baseball, basketball and boxing with ease. Despite all of this, Rio also shows somewhat of a childish side as well, shown by her fear of cats (this showing she has [[wikipedia:Ailurophobia|ailurophobia]]) and calling [[Reginald Kastle|Shark]] a "meanie" when he teasingly refused to help remove one from her sight. Rio tends to be annoyed when people refer to her as "Shark's sister" instead of calling her by name as indicated by [[Yuma Tsukumo|Yuma]] due to her snapping at him when he continually calls her as such, and especially does not like it when someone insults her brother. This is further seen many times during her Duel against [[Lotus Hanazoe|Lotus]] as she got mad at her for making a rude remark about Shark.

===Abilities===

As a [[Barian]], Rio possesses the ability to sense other Barians. This is shown when [[Girag]] arrived on [[Earth (planet)|Earth]], which caused her great pain and she foretold that "they" were coming to take "the most important thing".<ref name="ep74">{{episode|Yu-Gi-Oh! ZEXAL|74|ref}}</ref>

At another time, Rio and [[Reginald Kastle|Reginald]] visited a theme park where the former offered the latter one of [[Kastle twins' rings|two rings]] which they both could wear. Reginald initially refused to wear his ring, causing Rio to throw them on the ground and walk away in anger.<ref name="ep78">{{episode|Yu-Gi-Oh! ZEXAL|78|ref}}</ref>

Rio once [[Duel]]ed [[Quattro]] who was operating under the orders of [[Vetrix]]. He played the [[Spell Card]], "[[Flaming Hell Blessing]]", which set the surrounding area on fire. She was critically injured in the blaze, though Quattro carried her to safety, his face being scarred in the process.<ref name="ep58">{{episode|Yu-Gi-Oh! ZEXAL|58|ref}}</ref> After this, Reginald began wearing both of the rings from their childhood to remind himself of her.<ref name="ep78" />

Even after the [[World Duel Carnival]], Rio was still in the hospital, albeit with only bandages covering her eyes. Rio felt [[Girag]]'s arrival from the [[Barian World]], which caused her pain. Because of this, Reginald (who by now often used "Shark" as a nickname) arrived later along with [[Yuma Tsukumo|Yuma]] and [[Tori Meadows|Tori]] after him being called by the hospital as well as sensing Rio's pain. During that time Rio blurted out that someone is coming to take the most important thing, which worried Yuma as he had heard something similar [[The Door|before]].<ref name="ep74" />

Shark visited Rio at hospital again and gave her one of the rings from their childhood. She was later abducted by [[Art Stanley]], who was following Girag's orders and was imprisoned in a cage within Art's comic book. Art approached Shark and informed him of this, causing them to Duel. When Shark attempted to use "[[Zeus Breath]]", Art claimed that the comic world be destroyed if he lost - with Rio still inside it. Yuma and [[Ray Shadows]] went to Art's comic writing room and managed to find several pages detailing how the Duel would go, as well as the result, which resulted in the death of both siblings. However, Shark called out to her and their bond managed to shatter her imprisonment, making her appear on top of a tower on the "[[Comic Field]]" [[Field Spell Card]]. When her bandages are blown off of her face, she insulted Shark's Dueling skills. After the Duel, she collapsed and was carried away by Shark.<ref name="ep78" />

After her recovery, Rio was able to return to [[Heartland Academy]]. On her first day back, she intended to go with her brother, but he ran ahead without her. When she found him, she called him a jerk and told the gathered students he could never do anything without her. She ate lunch on the roof with her brother, Yuma and his friends. She spoke with Yuma, realizing he's the one who beat her brother earlier but believed him to be [[Kite Tenjo|Kite]]. When she found out who he really is, she recalled his catchphrase and then mispronounced it and became annoyed when Yuma referred to her as "Shark's sister". Their lunch was interrupted by a group of students representing various clubs, including [[Yata-Garasu (character)|Yata-Garasu]]. They wanted Rio to become their manager.<ref name="ep79" />

She agreed to visit each club, but would only join if they defeated her in the club's activity. By herself, Rio defeated the school's soccer team and various other clubs, chiding them for asking her to manage them when they can't play. She said that she had to be strong, as she didn't want anyone to use her weakness to get to her brother. She was then approached by members of the [[Floral Design Club]], who invited her to join them. When Rio and her friends arrived, they were introduced to [[Lotus Hanazoe]], the club's leader. The entire club had been hypnotized by Girag and Lotus put everyone to sleep. However, Yuma and Rio were both able to resist (and unbeknownst to either of them, [[Vector#As Ray Shadows|Ray]] as well). Though Lotus intended to Duel Yuma, Rio stepped in and challenged her instead. Despite Lotus' use of a "[[CXyz]]", Rio countered her moves and defeated her with "[[Ice Beast Zerofyne (anime)|Ice Beast Zerofyne]]". Yuma then nearly called her "Shark's sister" again, but accidentally called her "Shark's brother" instead. Though initially annoyed, she eventually laughed and told Yuma that she had heard that her brother had changed a lot when she was in the hospital. However, he went back to the way he was because of Yuma (in the dub, Yuma called Rio an "ice queen", initially upsetting her, but she forgave him because she had a sense of humor). As the group walked home, Rio saw a cat and hid behind her brother, frightened.<ref name="ep79" />

Rio participated in the "[[Friendship Games]]" held by Yuma and his friends, where she ended up on a team with Bronk. They would be defeated by her brother and Yuma during the Volleyball Duel, but they defeated [[Tori Meadows|Tori]] and [[Cathy Katherine|Cathy]] in the Wrestling Duel. Afterwards, she complimented the two on their plays.<ref name="ep81" /> Some time later, Rio went shopping at [[Heartland Shopping Mall|the mall]] with her brother. There, she sensed [[Mizar]]'s arrival on [[Earth (planet)|Earth]] and commented about a horrifying dragon. Knowing it had to do with the [[Barian]]s, they hurried to where Yuma was Dueling inside a [[Sphere Field]] generated by a [[Barian Sphere Cube]].<ref name="ep82">{{episode|Yu-Gi-Oh! ZEXAL|82|ref}}</ref> Rio watched the rest of the Duel, which Kite eventually took over for Yuma. She looked on in horror when her brother attempted to save Yuma from his fall and ended up falling down the cliff himself.<ref name="ep83">{{episode|Yu-Gi-Oh! ZEXAL|83|ref}}</ref> She visited her brother in the hospital while he was recovering.<ref name="ep84">{{episode|Yu-Gi-Oh! ZEXAL|84|ref}}</ref> One morning while talking to Tori at [[Heartland Academy|school]], Rio sensed that Yuma was in danger, therefore she, Tori and Shark rushed to aide Yuma and Ray at the [[Heartland Pier]] where they entered a [[Battle Royal]]. After they managed to defeat several Duelists, Girag intervened, forcing all of the brainwashed students to attack Yuma, however [[Alito]] intercepted, using a combination of "[[Lightning Clinch]]" and "[[Brain Reboot]]" to defeat the remaining Duelists. Rio watched Yuma's Duel against Alito afterward.<ref name="ep85">{{episode|Yu-Gi-Oh! ZEXAL|85|ref}}</ref>

Later at school, Shark was asked by Bronk to Duel him, who was trying to gain his blessings to date Rio but Shark declined since he was no match for him. He also added that Bronk was not even at Yuma's level, causing Bronk to jump to the conclusion that Rio was with Yuma. [[Flip Turner|Flip]] and [[Caswell Francis|Caswell]] overheard this and spread a rumor around the school. Oblivious to the misunderstanding, an angry Rio challenged Shark to a Duel. During the Duel, Shark was able to counter every strategy Rio played and voiced little faith in Rio's confidence as a Duelist. While Shark was proud that Rio was able to gain courage, he proclaimed that she still has a long way to go if she wanted to beat him and defeated Rio with his "[[Shark Caesar (anime)|Shark Caesar]]". Afterwards, Shark learned the rumor from Rio and cleared up the misunderstanding, clarifying that he was not the one spreading the rumor. Bronk then asked to Duel her one day and began to ask something in regards to what would happen if he won, but trailed off. Rio said she'd look forward to it. Upon finding out that Caswell and Flip had spread the rumor, Rio chased them down out of anger.<ref name="ep91">{{episode|Yu-Gi-Oh! ZEXAL|91|ref}}</ref>

During Heartland Academy's Fun Fair, Shark observed the play Rio was acting in and displayed irritation watching her with Yata-Garasu. When Bronk came to him, Shark was shocked by his cosplay as "[[Gogogo Golem (anime)|Gogogo Golem]]" and grew annoyed that he was calling Shark "brother." Shark's irritation prompted Rio to throw her shoe at Shark and tell him to be quiet.<ref name="ep92">{{episode|Yu-Gi-Oh! ZEXAL|92|ref}}</ref> After hearing about the [[Different Dimension Airship]] giving Yuma, Shark and Kite access to the [[Barian World]], Rio forced Shark to let her join them, surprising Yuma. During the trip, an array of monsters begin assaulting the ship. Seeing this, Rio and the others went to the exterior, using their ace monsters to battle with them. After this, the ship was sucked into a portal, transporting the group to "[[Sargasso the Different Dimension Battlefield (anime)|Sargasso the Different Dimension Battlefield]]" where she and Bronk supported Shark during his Duel with [[Dumon]].<ref name="ep95">{{episode|Yu-Gi-Oh! ZEXAL|95|ref}}</ref> Rio and the others returned to Earth after Vector's defeat.<ref name="ep98">{{episode|Yu-Gi-Oh! ZEXAL|98|ref}}</ref>

Rio's room in the hospital was broken into by [[Chironex]], who infected her with jellyfish poison in order to lure out Shark.<ref name="ep114">{{episode|Yu-Gi-Oh! ZEXAL|114|ref}}</ref> However after Shark and Quattro were able to defeat Chironex in a Duel, both siblings were cured. After his defeat, Chironex revealed Shark's and Rio's deaths on the day of the car accident to the former.<ref name="ep115">{{episode|Yu-Gi-Oh! ZEXAL|115|ref}}</ref>

While Shark was visiting Rio, Dumon appeared once again with the mission of making him remember more of his past. When this occurred, Rio became a spirit who watched over everything that happened in her brother's past life making her eventually regain her memories as well.<ref name="ep120">{{episode|Yu-Gi-Oh! ZEXAL|120|ref}}</ref> Soon afterward, when Dumon transported Rio and Shark to the Barian World, Rio started to cry after hearing Dumon say that she had to sever the bond she made with Yuma, and she also learned that she was one of the missing Barian Emperors, Marin, while her brother was Nash.<ref name="ep121">{{episode|Yu-Gi-Oh! ZEXAL|121|ref}}</ref> They spoke later, with Shark insisting that Rio call him "Nash". Both of them blamed their actions in their past lives for setting in motion the events of the present. Rio asked if he could really fight Yuma and his friends, and Nash vowed to do so "for the sake of the Barian World", throwing away the pendant that contained the picture of his family in the process.<ref name="ep125">{{episode|Yu-Gi-Oh! ZEXAL|125|ref}}</ref> Later, the other Barians called for an emergency meeting between themselves, with Vector arriving to discover to his horror that Nash and Marin had returned.<ref name="ep122">{{episode|Yu-Gi-Oh! ZEXAL|122|ref}}</ref> Dumon explained that they had ended up Earth and Nash confirmed his intent to lead the Barians again, proving his loyalty by suggesting Vector could kill him should he sense any hint of betrayal. Vector suggested they attack now, with Yuma and Astral gone, but Nash replied that he knew that they would be back. He granted the other Barian Emperors new powers, then agreed to Vector's plan.<ref name="ep123">{{episode|Yu-Gi-Oh! ZEXAL|123|ref}}</ref>

====Barian Emperor Onslaught====

After [[Mr. Heartland]] was defeated, the [[Seven Barian Emperors]] arrived together on [[Earth (planet)|Earth]] in front of [[Yuma Tsukumo|Yuma]]. Together, they commenced [[Barian Battlemorph]]. Yuma was rendered unable to Duel when the [[Emperor's Key]] reacted with [[Nash]]'s [[Barian Emblem]]. [[Roku]] and [[Kaze]] arrived and pelted the Emperors with smoke bombs, allowing Yuma's group to escape. The Emperors gave chase, with Marin being confronted by [[Bronk Stone|Bronk]], who insisted she would always be Rio to him. Marin unveiled her "[[Number 10X|Over-Hundred Number]]" [[Monster Card|monster]], "[[Number 103: Ragnazero (anime)|Number 103: Ragnazero]]" and later commenced a [[Chaos Draw]] alongside the others.<ref name="ep124">{{episode|Yu-Gi-Oh! ZEXAL|124|ref}}</ref>

[[File:DurbeandMeragEnergyBeams.png|right|200px|thumb|Marin and [[Dumon]] head towards a Duel.]]Marin traveled with [[Dumon]] and they were soon alerted to a Duel's start when they saw "[[Number 9: Dyson Sphere (anime)|Number 9: Dyson Sphere]]" in the sky. They quickly headed to that location to find Mizar Dueling Trey and Quinton. [[Mizar]] told them he was fine and that they should move on and pursue Yuma and Kite. Trey and Quinton used the power of their bracelets' [[crest]]s to generate a [[Sphere Field]], trapping the three Barians there. Mizar still told them not to interfere.<ref name="ep127">{{episode|Yu-Gi-Oh! ZEXAL|127|ref}}</ref> After the brothers managed to seal "The Seventh One" by equipping Mizar's "[[Number 107: Galaxy-Eyes Tachyon Dragon (anime)|Number 107: Galaxy-Eyes Tachyon Dragon]]" to "[[Number C6: Chronomaly Chaos Atlandis (anime)|Number C6; Chronomaly Chaos Atlandis]]", Dumon commented that "The Seventh One" should be unstoppable, with Marin adding they had indeed found its one weakness. He was shocked when they managed to reduce Mizar's Life Points to only 1 with "Chaos Atlandis". Mizar finally manged to recover "Tachyon Dragon" and Summon "[[Number C107: Neo Galaxy-Eyes Tachyon Dragon (anime)|Number C107: Neo Galaxy-Eyes Tachyon Draogn]]" to defeat them. The Sphere Field faded and Mizar told Dumon and Marin that he was heading to the moon to find Kite, after hearing of the [[Legend of the Dragons of Light and Time|legend]] the latter had gone to investigate.<ref name="ep128">{{episode|Yu-Gi-Oh! ZEXAL|128|ref}}</ref>

When Dumon and Marin arrived in the Barian World, they were greeted by [[Vector]]. He informed them he intended to unite the power of the Seven Emperors. Dumon responded that the seven were already united, but Vector corrected him, saying he would absorb all of their powers for himself.<ref name="ep130">{{episode|Yu-Gi-Oh! ZEXAL|130|ref}}</ref> Vector revealed that he had revived [[Don Thousand]] and that the Seven Emperors were simply his pawns to begin with. Dumon pointed out that that applied to Vector too, but Vector claimed that with Thousand's power, he was a god himself. Dumon suggested Marin flee to inform the others, but Vector clarified that Alito and Girag were working for him. The three Dueled in a [[Battle Royal]] style, though Marin and Dumon combined "Ragnazero" and "[[Number 102: Star Seraph Sentry (anime)|Number 102: Star Seraph Sentry]]" to destroy "[[Number 96: Dark Mist (anime)|Number 96: Dark Mist]]". However, Vector Summoned "[[Number 43: Manipulator of Souls (anime)|Number 43: Manipulator of Souls]]" and [[equip]]ped "Dark Mist" to it before recovering his [[Life Points]] using the [[Continuous Spell Card]] "[[Don Thousand's Throne (anime)|Don Thousand's Throne]]", which drew its power from [[Reginald Kastle|Nash]], who is held captive within a [[Sphere Field]], which in turn increased the monster's [[ATK]] and deals [[effect damage|damage]] to Marin. Vector revealed his "point" system and the fact that he had killed Nash and Marin previously. Marin, enraged by Vector's words, used "The Seventh One" to bring out "Ragnafinity".<ref name="ep131">{{episode|Yu-Gi-Oh! ZEXAL|131|ref}}</ref>

[[File:NaschandMerag'sSpirit.png|left|200px|thumb|Marin's spirit appears with Nash.]]

===Reginald Kastle===

[[Reginald Kastle|Shark]] and Rio are twins and share a strong bond ever since they were children, symbolized by matching [[Kastle twins' rings|rings]] that Rio obtained.<ref name="ep78" />

Despite their bond, Shark has a typical tenuous "brother-sister" relationship with Rio, irritating one another and having normal siblings squabbles.<ref name="ep78" /><ref name="ep79" /> If these squabbles escalate, they settle them through a Duel and have done so a total of one hundred times.<ref name="ep91" />

===Bronk Stone===

[[Bronk Stone|Bronk]] is one of [[Yuma Tsukumo|Yuma's]] friends, and as a result is also an acquaintance of Rio. However, Bronk has a crush on Rio, which he developed when he saw her return to [[Heartland Academy]].<ref name="ep79" /> This infatuation developed further when Rio helped him with an injury on the way to school. From that point on, he had been trying to develop a relationship with her, and actually asked [[Reginald Kastle|Shark]] for his permission to ask her out. However, Shark refused and this actually led to a clash of the siblings.<ref name="ep91">{{episode|Yu-Gi-Oh! ZEXAL|91|ref}}</ref> Since then, Bronk has made no significant moves toward her and they remained friends. However he later started calling Shark "big brother", pretending he was his brother-in-law.<ref name="ep92" />