Yu☆Gi☆Oh! Zexal Second: Iza! Saishuu Kessen e!! Special

A mysterious spirit that Yuma encounters, who only Yuma can see or hear. He is a duel genius and offers his wisdom to Yuma, whose duel tactics are lacking, in order to obtain the 99 Numbers Cards which contain fragments of his memories.

Astral

Ryouga is one of Yuuma's close friends and rivals. After being disqualified from the National Duel Circuit, Ryouga became bitter and uncaring, the way he held himself at the beginning of the series. Cold and malicious, Ryouga flaunts his power by taking the Decks of the people he defeats. Once he's defeated by Yuuma in the second episode, and the 'numbers' possessing him is taken, he returns to his more humble self.  Ryouga holds an intense hatred towards IV for setting him up to be disqualified and implying that he intentionally hurting his younger sister. After learning this from IV himself, he entered World Duel Carnival and became more cold and more brutal to any duelist he challenges, even considering Yuuma his enemy.  (Source: Yu-Gi-Oh Wikia)  It was later revealed that Shark is king of the Barian World, Nasch. Originally born as Nasch, he was once the ruler of the United Lands of the Poseidon Ocean alongside his sister, Merag and was well-loved by his people. One day, his kingdom was attacked by Vector, who led a fleet of ships and several "Gorgonic Guardians" to lay waste to it and loot it. Nasch ordered a counterattack, arming his soldiers with mirror shields which turned the gorgons' abilities against them. Vector performed a blood sacrifice in response, calling forth the ocean god, Abyss, turning the tide of the battle again. Merag rode up to Abyss and was grabbed by him. Despite the intervention of Nasch's friend, a knight named Durbe, Merag did not want to be saved and sacrificed herself to call forth another god to purify Abyss.  After Merag's funeral, Nasch declared an attack on Vector's kingdom in retribution, as the latter has fled with the god turned to Nasch's side. Once they got to a town ravaged by Vector's army, Nasch noticed a little girl crying, who strongly resembled Merag. Nasch took the young girl, Iris, under his care and wondered if she was his deceased sister's reincarnation or if she was sent by Merag herself. As Nasch and his army pursued Vector, Nasch grew close to Iris and planned to confront Vector by himself once the battle started. On war front, Nasch followed Vector to a secret tunnel in what would eventually become a Number ruins, where Vector challenged him to a Game of Darkness. Per the Duel's rules, the more monsters of either ruler that were sent to the Graveyard, the more soldiers their army would lose. Though Nasch was victorious, his entire army was lost due to Vector's mill strategy. Their souls were sent to the Barian World. Vector barely survived and limped back to his own country, prompting Nasch to follow him. There, he found Vector had killed all of his own people. He also witnessed Vector being dragged to the afterlife by the people he murdered  An unknown number of years later, Don Thousand reincarnated both he and his sister as two of the Seven Barian Emperors, as their souls were each connected to a Legendary "Number" card, which had sealed Thousand's power. Nasch then became the leader of the Seven Barian Emperors, much to Vector's disdain (also having been reborn as a Barian Emperor). After Nasch had annoyed him enough to score 100,000,000 points, Vector enacted his revenge by taking Merag hostage. When Nasch intervened, Vector used "Giant Sky Sword" to open a bottomless rift. He then pushed Merag from the cliff, forcing Nasch to follow after her only for the two to be sucked into the rift. The two were rescued by Abyss, who informed them that he would send them to the Human World without their memories, where their souls were then revived in the bodies of Kamishiro Ryouga and Rio, who had recently died in a car accident. While Vector believed them dead, Durbe believes they had simply disappeared and assumed leadership of the group from them in the interim, waiting for their return.  (Source: Yu-Gi-Oh! Wikia)

Ryouga Kamishiro

Yuuma Tsukumo is the main character of Zexal. Yuuma lives with his older sister and grandmother, because he lost his parents, who were archaeologists. A necklace that his parents gave him seems to hold many secrets. His dad also left him with his deck. Despite the lack of parents, Yuuma is usually a happy and energetic child, who hates unfairness and cares about his friends. He never gives up and always shoots for the top. Unfortunately, he doesn't always make it. His goal is to become the world champion of dueling and has some of the cards he needs to do so, but, unfortunately, he is not a very good card player. Because of this drawback, he will often put himself in a tough position, such as facing against his tough future rival, Shark Ryouga. Yuuma teams up with the mysterious Astral, who is conveniently a dueling genius. Even though Astral tries to help Yuuma, he often does not listen because of his extreme stubbornness and wrongful pride. Although they have conflicting personalities, Yuuma needs to learn to work with Astral, and put aside his pride or he will never be a dueling champion.

Yuuma Tsukumo

He is one of the Seven Barian Emperors of the Barian World.

Alit

Durbe

The will of the Astral World. As such, he governs the entire realm and rules it with the purpose to Rank it up by destroying the Barian World.

Eliphas

Gilag is one of the seven Barian lords of the Barian world. He is a fearless warrior who does not hesitate in his mission. Despite the fact he's a warrior he seems to prefer using others to do his work. Gilag also seems to be quite arrogant as he referred to himself as "ore-sama".

Gilag

Yu☆Gi☆Oh! Zexal Second: Midokoro Tenkomori Special

Recap of first 8 episodes of the second season, narrated by Yuma and Astral.