Union Arena is a trading card game from Bandai that launched in 2024 as a sibling to Bandai's other collectible titles, built around crossover-friendly structure and series-based decks. Its Demon Slayer: Kimetsu no Yaiba set arrived in 2025 and drew on one of the most widely read manga and anime franchises of the past decade, bringing its cast of demon hunters and breathing techniques into a format that rewards both casual play and collecting. Sets like this are remembered in the hobby as the point where a fresh game and a beloved license met, and many collectors chase them as a snapshot of how anime-linked card games were finding their footing in this period. Giyu Tomioka, the Water Hashira and one of the franchise's most recognizable swordsmen, is a fitting subject for a Super Rare slot. Fans know him for his reserved demeanor, his disciplined Water Breathing style, and a backstory that shapes much of the series' emotional weight. Collectors tend to seek out his cards for exactly that reason: he is a character whose presence on the table carries the tone of the source material.