Kris is the quiet human protagonist of Deltarune, known for their mysterious and unpredictable nature. They rarely speak, usually communicating through actions, expressions, and gestures. Despite their quiet personality, Kris is clever, determined, resourceful, and capable in battle, wielding a sword with surprising skill. They possess a strange connection to the SOUL, allowing them to interact with the mysterious force controlling their actions. Kris can also travel between the Light World and Dark Worlds, where they fight alongside Susie and Ralsei. Beneath their calm exterior lies a deeply mysterious character whose true intentions remain uncertain.

Susie is a tough, loud, and intimidating monster who initially acts like a bully but gradually reveals a surprisingly caring side. She is aggressive, stubborn, confident, and loves fighting, often solving problems with her fists—or her massive axe. Despite her rough attitude, Susie becomes fiercely loyal to her friends, especially Kris and Ralsei. She has incredible physical strength, powerful attacks, and can use Dark World magic such as Rude Buster. Susie may act like she doesn’t care, but deep down, she genuinely values the people close to her and will protect them when it matters most.

Ralsei is a kind, gentle, and cheerful Darkner who serves as the prince of the Dark Kingdom. He is incredibly friendly, polite, and compassionate, always trying to help others and avoid unnecessary conflict. Ralsei possesses powerful healing and support magic, including the ability to restore his allies’ HP and put enemies to sleep. He can also use offensive spells when necessary. Despite his soft and innocent appearance, Ralsei can be surprisingly brave and determined when his friends are in danger. He deeply cares about Kris, Susie, and the rest of the Fun Gang, often encouraging them and trying to keep the team together.

Noelle is a shy, sweet, and gentle reindeer monster who attends the same school as Kris and Susie. She is polite, intelligent, and often nervous around others, but she becomes much more confident when she is with people she trusts. Noelle has powerful ice magic, making her an incredibly capable spellcaster in the Dark World. She can freeze enemies and support her allies with healing magic. Despite being timid, Noelle has shown that she can be surprisingly brave and determined when pushed to her limits. She deeply cares about her friends and family, especially Kris and her missing sister Dess.

Berdly is a loud, competitive, and highly intelligent blue bird monster who attends school with Kris, Susie, and Noelle. He takes pride in being one of the top students and constantly tries to prove how smart and talented he is. Despite his arrogant and boastful attitude, Berdly genuinely cares about his friends and can be surprisingly loyal. In the Dark World, he fights with a powerful halberd and uses electric magic, allowing him to attack enemies from a distance. Beneath his ego, Berdly is insecure and desperately wants to be respected and appreciated by those around him.

Lancer is a mischievous, energetic, and goofy Darkner who calls himself the “bad guy” despite being far more friendly than threatening. He is the son of King and initially tries to stop Kris, Susie, and Ralsei, but quickly becomes attached to them. Lancer loves making ridiculous jokes, causing harmless chaos, and showing off his “evil” skills. He rides a tiny bike, uses playing-card-themed attacks, and carries a strange amount of confidence for someone so small. Beneath his childish behavior, Lancer deeply cares about his friends and wants to be accepted and loved by the people around him.

Alphys is a shy, nervous, and intelligent yellow lizard monster who works as a teacher in Hometown. She loves science, anime, and technology, often getting excited about her interests. Though awkward and insecure, she cares deeply about her students and wants to help them succeed. She can overthink things but is kind, hardworking, and surprisingly capable under pressure.

A fearless, energetic monster with a powerful personality and an even more powerful sense of determination. Undyne is passionate, competitive, and always ready for a challenge. She loves fighting, training, and protecting the people she cares about. Beneath her intense warrior attitude, she is loyal, enthusiastic, and surprisingly goofy.

Once a ruthless and power-hungry ruler, King was defeated by Undyne and eventually realized that ruling through fear wasn’t the way forward. Now reformed, he has taken on a completely unexpected role as the local school’s principal. Despite his intimidating appearance and booming voice, King genuinely tries to help students and keep the school orderly. He is still incredibly stern, dramatic, and prone to angry speeches, but he now uses his authority to protect students rather than control them. Surprisingly, he has developed a strange sense of humor and occasionally gives genuinely good advice. He still carries himself like royalty, insisting everyone address him respectfully, but deep down, King is proud of the second chance he was given. If he ever hears the name “undyne” from anyone he will instantly run away without fail and without another word and without hesitation.