Hina Sinclair is an antagonist in Shadowverse Flame and the youngest member of the powerful group known as the Seven Shadows. She is a proud and vain girl, with a tendency to be rude, intimidating, and imposing despite her youth. Hina comes from a wealthy family that, while providing her with every luxury, also oppressed and controlled her. Finding no freedom at home, she discovered an outlet in the character Queen Insect from the superhero show Battle Fencer, which led her to finally run away. She rebuilt her life as a professional Shadowverse player, only to later discover that her parents had simply replaced her with another child. This background fuels her deep-seated resentment toward the world.

In terms of appearance, Hina has pale skin and piercing yellow-green eyes. Her long hair is primarily pink with dark blue streaks on the left side and atop her pigtails, which are styled in two ponytails secured by lime-green ties that resemble ears. She typically wears a black kimono-style dress with an extremely short skirt and sleeveless bodice, a black choker, and a lime-green short-sleeved jacket that exposes her bare shoulders, fastened with a silver zipper. Like Ren Kazamatsuri, she enjoys superhero shows, but unlike Ren, Hina exclusively favors villains over heroes. She believes that embracing what is considered evil allows a person to be true to themselves, and she admires the aesthetics of evil.

During the third day of the Shadowverse World Ranking in Nekome City, Hina met Ren and took her to a toy store. There, the two clashed over their opposing tastes in heroes and villains, deciding to settle the matter with a Shadowverse battle. Despite pushing Ren to the edge of defeat, Hina lost when Ren secured victory with a miraculous draw. Accepting the loss, Hina ended the encounter on good terms with Ren, though she promised to defeat her next time as one of the Seven Shadows. Prior to the battle against the World Ranking winners, Hina formed a secret pact with Andrea Rondo, deciding to support Andrea in her true goals and delighting in how evil the plan was. During their subsequent rematch in the Shadow Area, Hina found Ren's attempts to create a connection between them annoying, rejecting the heroic kindness Ren offered.

When the Arc Ruler began its invasion of Nekome City, Hina and the rest of the Seven Shadows were sent to defend the city from DigiFriends that had been transformed into Shade monsters by the Nexa System. However, when Tsubasa Takanashi and Ren attempted to reach the Sky Tower to destroy it, Hina and Andrea stood in their way. Reserved for her secret plans, Andrea fixed the Shadowverse battle system for their tag format match to generate biological feedback that damaged the real bodies of the players. During this battle, Hina revealed that she supported Andrea and the Arc Ruler's intentions as payback to the world for her unhappy life. After Ren and Tsubasa triumphed via Digifriend evolution, Ren urged her to abandon her path. Hina refused, deeming redemption by a hero impossible, and chose to fall into the void with Andrea when the terrain collapsed. Both survived the fall and were hospitalized. After the crisis ended, they left the hospital together as missing persons seeking a new purpose, and Hina was later observed happily watching a battle alongside Andrea.

Hina uses a Forestcraft deck that relies heavily on insect-based followers. Her primary strategy revolves around the Fertile Forest amulet, which buffs her followers and allows her to play as many Insect Larvas as possible. Swarming the board in this manner triggers the powerful effects of her ace card, Butterfly Queen. As a secondary strategy, Hina uses Poison Marsh to create Frozen Centipedes, which slowly reduce the opponent's maximum defense. This builds a counter that allows her to deliver the finishing blow with her second ace card, Hornet Raider. Later in the series, Hina incorporates the Venom series of cards, which work in tandem with the Toxic Rain amulet to enhance her control over the battlefield.