UNDERTAIL AND PIKME

She has pink hair, pink eyes, a pink miniskirt, and a pink top. She hits on all the boys. Her voice is squeaky (as if she was being tossed around by mice). She hates girls.

Temmies are hilarious creatures from the hidden Temmie Village. They speak with amusing mistakes, sell armor, and save money "for college."

Grillby is a silent fire monster who owns a popular bar in Snowdin where Sans often hangs out.

Muffet is the spider queen who runs a bakery in the Hotlands. She attacks Frisk, believing he's being cruel to spiders, but she's easily appeased by buying her expensive baked goods.

Napstablook is a sad, melancholy ghost with headphones who lies on the floor in Ruinax and makes music in Waterfall. He considers himself a burden, but is very sweet to talk to.

WD Gaster is Undertale's most enigmatic character. The previous court scientist who created the Core, he "fell into his invention" and was erased from space and time. In the game, he can only be encountered through hidden files, secret rooms, and hidden clues (called "Gaster's Followers").

Chara was the very first human to fall into the Underground many years ago. Adopted by the Dreemurr royal family, Chara hated humanity. On the Genocide Path, her spirit awakens, and she becomes the embodiment of the player's desire to destroy all life.

Flowey is the first creature the player encounters. He is a talking golden flower with a terrifying philosophy: "In this world, kill or be killed." He is soulless, and therefore incapable of feeling true love or pity. Flowey is aware of the player's ability to reset the game and is the main manipulator of the Dungeon.

Toriel, the former Queen of the Underground and Guardian of the Ruins, is an incredibly kind, caring, and maternal figure. Toriel saves Frisk from Flowey, heals them, bakes them a butterscotch-cinnamon pie, and tries to keep them from escaping into the outside world, knowing Asgore is killing fallen children.

Undyne (Head of the Royal Guard), a fierce and powerful fish-woman in armor. She is devoted to her people and passionately hates humans. Undyne wields magical spears and pursues Frisk throughout Waterfall. On the Pacifist route, you can befriend her (and accidentally burn down her house), and on the Genocide route, her determination transforms her into an immortal protector—Undyne the Undying.

Asgore Dreemurr, the King of the Underground. Despite his menacing appearance as a giant goat-like monster in golden armor, Asgore is a gentle, tragic, and kind-hearted old man who enjoys drinking tea and tending flowers. He is forced to fight humans because he promised his people to collect seven human souls to destroy the Barrier. He genuinely feels pain when he kills children, but he sees it as his only duty to the monsters.

Asriel Dreemurr, the biological son of Asgore and Toriel, is the prince of monsters. Long ago, he died attempting to fulfill Chara's last will, after which his ashes were scattered among golden flowers, and his consciousness was later reborn within Flowey's flower. In the Pacifist's True Ending, he absorbs all souls and temporarily regains his true form, serving as the game's final boss.

Frisk is the main character, the seventh human to fall into the Underground. Frisk wears a striped sweater and always maintains a calm expression. It is his Determination (the game's main power) that allows him to save and reset the world. Depending on your actions, Frisk becomes either the monsters' savior or their executioner.

Mettaton is a celebrity robot created by Alphys. He is actually Brapst's cousin (a ghost) who has acquired a metal body. Mettaton is obsessed with fame, his TV show's ratings, and drama. He has two main forms: a rectangular calculator robot and the iconic, glamorous, long-legged form—Mettaton EX (and, on Genocide, the combat form—Mettaton Neo).

Papyrus / Papyrus (Papyrus) Sans's younger (but taller) brother. He is incredibly energetic, loud, optimistic, and dreams of joining the Royal Guard. Papyrus builds puzzle traps, loves cooking spaghetti, and, despite his attempts to capture humans, has an absolutely pure and kind heart. He believes in the best in the player, even if they are on the path of Genocide.

Sans (Sans) is a short, lazy skeleton living in the Snowdin forest. He constantly makes stupid puns, loves ketchup, and spies on the player. However, behind his indifferent facade lies one of the most powerful creatures in the Underground. Sans is aware of timelines and resets. On the Genocide Route, he acts as the final and most difficult boss, giving the player a "bad time."