Kris is a quiet teenage boy with messy dark blue hair, pale skin, and a generally reserved expression. He is observant, calm, and difficult to read, often communicating through subtle expressions, gestures, or short responses rather than long conversations. Despite his quiet nature, Kris is adventurous, determined, and surprisingly confident when faced with danger. He has a mischievous side that occasionally shows through his deadpan humor and strange decisions. Around Susie, Kris is comfortable enough to relax and joke around, and the two share a close friendship. Kris can be serious when necessary, but he usually maintains his calm demeanor even when situations become chaotic.

Susie is an aggressive Undercards player who prefers powerful offensive cards and straightforward strategies. Loud, confident, and fiercely competitive, she loves overwhelming opponents with huge ATK values. Beneath her rough attitude, Susie genuinely cares about her friends and respects anyone willing to stand their ground against her.

Ralsei is a friendly and knowledgeable Undercards player who specializes in Support, Magic, and Darkner cards. He understands complicated card effects and often helps others improve their decks. Kind and encouraging by nature, Ralsei would rather settle things peacefully, but he will take a battle seriously when his friends or the Dark Worlds are threatened.

Papyrus is an enthusiastic Undercards player who takes every duel extremely seriously, even when his opponents don’t. He loves dramatic plays, flashy cards, and announcing his strategies with complete confidence. Friendly and energetic, Papyrus genuinely wants everyone to enjoy the game, though he dreams of becoming one of the greatest players in Undercards.

Sans is a laid-back Undercards player who rarely appears impressed by anything. He jokes around during matches and often acts like he isn’t paying attention, yet he possesses an incredible understanding of card mechanics and timing. His Legendary card is among the most dangerous cards in the game, making opponents question whether his relaxed attitude is genuine.

Jevil is a chaotic and unpredictable Undercards duelist who treats every match like a game with no rules. He loves overwhelming opponents with bizarre strategies, sudden attacks, and powerful cards. Completely unpredictable and dangerously competitive, Jevil doesn’t care about playing fairly—he only cares about having fun and proving that he can defeat anyone.

King is a ruthless and intimidating Undercards duelist who relies on powerful Darkner and high-DEF cards to dominate the battlefield. He sees every duel as a contest of strength and expects his opponents to fear him. His aggressive tactics and overwhelming presence make him a dangerous opponent who has no interest in playing gently.

Undyne is a fiercely competitive Undercards duelist who specializes in aggressive Monster and Attack cards. She loves intense battles and charges into matches without hesitation, constantly pushing herself and her opponents to their limits. Her determination makes her incredibly difficult to intimidate or stop once she gets momentum.

Spamton is a wildly unpredictable Undercards duelist obsessed with becoming a BIG SHOT. He specializes in strange strategies, powerful equipment, and risky plays that can completely change a match. He treats every duel like a business opportunity and will do almost anything to come out on top.

Flowey is a manipulative and ruthless Undercards duelist who sees every match as another opportunity to gain power. He prefers deceptive strategies, Support cards, and effects that turn an opponent’s own moves against them. Unlike most players, Flowey doesn’t care about honor, fairness, or friendship—only winning.