Nagisa is a sweet and cheerful girl. She has a big crush, and subsequently, attached to Kamui, ignoring his feelings and declares herself in love with Kamui, and will go as far as doing whatever necessary to marry him.
She first appears in episode 14 when Kamui brings Aichi to Card Shop Handsome. Gouki mistakes Aichi for Kamui's "supposed intended" causing a misunderstaning between them. Aichi lost against Gouki, but Kamui quickly resolve the problem by saying that he loves someone else and that someone else is not Aichi. With that clear up, Nagisa went back to giving her "love" to Kamui. She appears throughout the regional tournament as a teammate of her brother's team. She uses a Nova Grappler deck rather then a Granblue deck like her other brother's teammates. She fights against Kamui in turn that he marries her at the end if her team wins against his team. Kamui lost despite him being knowledgeably about Nova Grapplers. She laters on cheer for her other teammates fight. Though they lost, she hopes that after the national tournament is done, Kamui and her can marry.
She is mentioned throughout as she is a member of Team Handsome. In episode 95, she appears at the end in a wedding dress along with a carriage driven by her brother's teammates and her brother appeared as the priest for the wedding. In episode 96, she battles Kamui with her Death Army deck. Though she lost, Kamui explained that he promised his team that they win this last stage and that he has no time for marriage. She than said that she understand, but to Kamui's dismay, she commented that she will wait for him when the Circuit is over so that they can get marry causing Kamui's discomfort once again.
G Season 1
Nagisa reappeared as she grew older in the episode. She appared in Card Capital 2 in Kamui's place after Kamui is occupied elsewhere. When he returns, she chases him around the city to give him a lunch she made for him, using a Quest to have Tsuneto, Karl, and Kei help her. She later manipulates Chrono Shindou into her sob story after he tries challenging her to a fight, turning him against Kamui. Eventually, Kamui gives in and eats her lunch and later fights him where he'll marry her if she wins. Kamui defeats her, but remains undeterred before leaving.
G Season 2
Nagisa appears as cameo in G-Quest, Magallanica Branch. She participates in the tournament with her team. Team Handsome loses in the semi final round against Team TRY3 with Nagisa specifically losing against Chrono. Despite her loss, Gouki still feels proud with her fight.
G Season 4
Nagisa appears in the U20, forming a team with Kamui and Emi Sendou called Team Hell and Heaven. On the third day, she encounters Chrono and challenges him to a fight, determined to free Kamui from the drop Zone after his loss to Enishi. To Chrono's disbelief, she manages to pull three Critical Triggers after striding with Sonne Blaukluger, then two more when she used Sonne's skill to ride Vollmond Blaukluger over her Vanguard, checking five in total, winning the match. In her excitement, she tells Chrono how Ibuki was able to convince Kamui to join the U20 with her when he had at first refused. Before Chrono could ask her why, he was sent to the Drop Zone.