Undertale Yellow Characters and Bosses
Undertale Yellow introduces 'dozens of brand new characters'. Here's who you'll meet, where, and what role they play — with major story twists kept out unless you've already read the routes page.
Checked against official sources: November 8, 2026
Main characters
Clover
Protagonist · Yellow SOUL (Justice)
A child who climbs Mount Ebott with a missing-person poster to find out what happened to the five humans who vanished. Clover carries a toy gun and wears a cowboy hat "at all times", as the official page jokes.
Flowey
Companion · Neutral final boss
A talking golden flower who, unlike in UNDERTALE, starts out friendly: he follows Clover and saves the game for them. He comments on your choices throughout, is a supporting character on Pacifist and becomes the final boss of the Neutral route.
Martlet
Royal Guard · Snowdin boss
A blue bird monster and newly appointed member of the Royal Guard, serving as the game's deuteragonist. She first confronts Clover in Snowdin and keeps reappearing; on Pacifist she promises to convince Asgore that Clover is a good person.
Starlo ("North Star")
Sheriff · Wild East boss
The star-shaped sheriff of the Wild East, who adopted a cowboy persona after finding human Western movies. He leads the Feisty Five and puts Clover through a series of tests before their duel.
Ceroba Ketsukane
Ally · Pacifist final boss
A fox-like monster in a white kimono, the widow of scientist Chujin and mother of Kanako. She helps Clover for much of the journey, but her goal of continuing Chujin's work puts her on a collision course with them. On Genocide she replaces Starlo as the Wild East boss.
Dalv
Dark Ruins boss
A purple, vampire-like monster in a hooded cloak who lives alone in the Dark Ruins. Socially awkward, he claims to want solitude while wondering whether anyone ever cared about him. Spared, he may move to Snowdin; his dialogue changes with your kill count.
Clover's character sheet
Bosses and minibosses
Decibat
Miniboss · Dark Ruins
A shy, four-winged bat who values peace and quiet — the first miniboss, mirroring UNDERTALE's Napstablook.
El Bailador
Miniboss · Dunes
A muscular luchador-style dancer fought at the end of the East Mines, with a blue, green and red dance-mat mechanic.
The Feisty Four
Minibosses · Wild East
Ed, Moray, Ace and Mooch — Starlo's posse. With him they form the "Feisty Five" (Fearlessness, Excellence, Intuition, Sneakiness, Toughness, Youthfulness and Justice; "the J is silent").
Guardener
Miniboss · Steamworks
Guardener Model 02, an old, legless defense robot overgrown with plants who protects the Greenhouse — and escalates a squished flower to a "level 10" threat.
Axis
Boss · Steamworks
Axis Model 014, the last of a line of mechanical royal guards built by Chujin Ketsukane. He chases Clover through the Steamworks on Pacifist; on No Mercy the tables turn.
Macro Froggit
Optional miniboss · Steamworks
Appears on Pacifist and Neutral if you carry the Golden Pear, Golden Coffee and Golden Cactus.
Which final boss you face depends on your choices — see Undertale Yellow routes and endings.
Other characters
- Chujin Ketsukane — Ceroba's late husband, a scientist whose secret research drives much of the late-game story. He built Axis and the Steamworks guard robots.
- Kanako — Ceroba and Chujin's daughter. What happened to her is central to the Pacifist route.
- Dina — Runs the shop inside the Wild East saloon.
- Toriel & Asgore — UNDERTALE characters who return: Toriel guides Clover through the upper Ruins, and Asgore is the king who has already collected five human SOULs.
Regular monsters include Froggits in the Ruins and new faces such as Frostermit, Insomnitot, Know Cone and Trihecta in Snowdin. The game also hides cameos from other fan games: Red from UnderTale RED lives in Oasis Valley, and Cooper from Undertale Green appears too.
Characters FAQ
Who is the main character of Undertale Yellow?
Clover, a human child with a yellow SOUL of Justice. Their official character sheet lists ATK: Toy Gun and DEF: Worn Hat — the cowboy hat they wear the whole game.
Is Clover a boy or a girl?
Clover is referred to with they/them pronouns in the official Game Jolt description ("they find themself deep within the Underground").
Who is the villain of Undertale Yellow?
It depends on the route. Flowey is the final boss of the Neutral route, Ceroba Ketsukane is the final boss of the Pacifist route, and Asgore is the last fight of the Genocide route.