Main Characters
This page introduces the main cast players meet across a typical Undertale journey. Minor spoilers for early areas are hard to avoid; deep ending spoilers are marked.
Frisk
The human protagonist you control. Frisk wakes in the Underground after falling from Mt. Ebott. Combat uses FIGHT, ACT, ITEM, and MERCY. Your choices — not a fixed morality meter alone — shape who survives and which ending you reach. The yellow SOUL in battle is yours to steer through bullet patterns.
Toriel
Caretaker of the Ruins and former queen. She teaches puzzles, saving at glowing stars, and the idea that violence is optional. Leaving the Ruins is an emotional beat as much as a tutorial exit — talk to her thoroughly before you go.
Sans & Papyrus
Skeleton brothers tied to Snowdin humor, puzzles, and later story weight. Papyrus runs puzzles (badly), cooks spaghetti, and wants friends in the Royal Guard. Sans watches more than he says, sells hot dogs in odd places, and keeps score of your behavior across resets. Their dynamic is comedy first, then something heavier.
Undyne
Head of the Royal Guard. Waterfall pursuits and spear patterns define her presence. She believes in justice, heroism, and anime-sized feelings. ACT options, cooking side stories, and persistence matter as much as dodging. Befriending her is a pillar of the peaceful path.
Alphys
Royal scientist associated with Hotland screens, Mettaton, and True Lab threads. She loves human culture, hides insecurity behind monitors, and her arc rewards patience and exploration. Spoiler note: deeper Alphys content sits behind late-game doors — finish the surface ending first if you want discovery intact.
Mettaton
Hotland’s glamorous robot celebrity. Quiz shows, cooking segments, and stage fights mix entertainment with danger. Ratings, ACTs, and showbiz logic matter as much as ATK numbers.
Asgore & Flowey / Asriel
King Asgore Dreemurr rules from New Home and stands at the end of many Neutral paths. Flowey the flower is often the first face you meet — cheerful, then cruel — and sits at the center of Undertale’s themes about determination and consequence. Major spoilers: Asriel’s full story is late-game territory. Finish your first ending before reading deep theories.