TV-Series
Description
Ren Kazamatsuri, a first-year Shadoba College student, initially enrolled in the Fifth Sword club due to her athletic interests. There, she faced isolation as male members underestimated her and female members showed little training enthusiasm, prompting her to contemplate departure. Her situation shifted during a plaza raffle event where she met Light Tenryu and his friends. After winning prizes they desired, they traded, and Ren shared her struggles. Light invited her to join the Seventh Flame club, leading to a confrontation with Fifth Sword leader Tatsumi Raido. Following Tatsumi's defeat in a Shadowverse battle by Itsuki Mitsutagawa, Ren secured permission to transfer to Seventh Flame while preserving friendships with her former clubmates.

Ren possesses an energetic, kind, and considerate personality. She is often loud and easily overexcited yet consistently maintains a cheerful, positive attitude. Her personal interests, particularly a strong passion for hero-themed stories and sports, diverged from traditional feminine activities, causing social discomfort and hesitancy to share her enthusiasms. This stemmed from childhood; frail health led her to draw courage from the "Battle Fencer" hero show, inspiring her to overcome her challenges and become braver. After joining Seventh Flame, she gradually embraced her passions without shame.

Within Seventh Flame, Ren actively sought connections, particularly with the reserved Tsubasa Takanashi. She encouraged Tsubasa to engage in Shadowverse battles, using her own passion to break through Tsubasa's cold exterior. Their friendship deepened through collaborative investigations, like uncovering the true identity of Gentleman. Ren also supported club activities, participating as Seventh Flame's third representative in the Shadowverse Club Tournament. Her battle against Tatsumi Raido there became a significant moment for openly showcasing her dedication.

Ren competed in the Shadowverse World Ranking with an equal win-loss record initially. During this event, she formed a complex relationship with Hina Sinclair, whom she admired as a "Battle Fencer comrade." Their contrasting hero versus villain preferences culminated in a Shadowverse battle; Ren achieved an unexpected comeback victory, securing sixth place. She later defended her rank against Vivian Joubert. Her desire to connect with Hina persisted during the conflict against the Seven Shadows, though Hina initially rejected her.

Assigned to the Sky Tower team alongside Tsubasa during the Arc Ruler and Shades invasion crisis, they were intercepted by Hina and Andrea. A high-stakes tag battle ensued, involving biological feedback causing real physical damage. Despite attempts to reason with Hina and Andrea about their nihilistic views, Ren and Tsubasa emerged victorious. A subsequent battlefield collapse sent Hina and Andrea falling into a void; Ren tried to save Hina, but Hina deliberately let go, declaring it "too late for the hero to save her." This failure deeply affected Ren, influencing her emotional response when Light Tenryu prepared to face Wolfram Zerga alone. She pleaded with Light not to shoulder the savior burden, explicitly citing her inability to rescue Hina as proof of heroism's limits. Ultimately, she supported Light in the final battle, using her Swordcraft ace card, Amerro, Spear Hero, to help clear the path to victory.

Ren utilizes a Swordcraft deck focused on "Heroic" followers that capitalize on damaged allies on the field. Her strategies involve swarming the board through play point restoration and cost-reduction combos. Her signature card is Amerro, Spear Hero, and her DigiFriend is Valiant Fencer. Following the resolution of the world-threatening crisis, Ren agreed to keep the events secret to preserve normalcy. She later participated in a celebration with Seventh Flame and observed the climactic battle between Light and Mikado.