Undertale Halloween Costume Ideas: Which Character Should You Be? (2026)

Not sure who to be? Let your soul decide.

The Soul Virtues quiz asks 66 questions about everyday choices, scores all seven virtues at once, and names the one carrying you. Each virtue is one soul color, and each color is one character below. No game knowledge needed; it takes about eight minutes.

♥ Take the quiz, get your character

Free, no sign-up. Your result page shows the costume match right under your scores.

Know your soul color? Here's your character.

The match is by personality, not by outfit color. Determination refuses to stop, so it gets the kid who never stopped. Kindness protects, so it gets the mother who blocks the door. Read the line under each name and you'll see why.

Your soul is red · Determination

Go as Frisk

Determination is the red soul: the power to keep going after every reset. If your spread says you don't let an ending stand, neither does Frisk.

Striped shirt (blue, two pink stripes), blue shorts, brown shoes, a stick.

Full Frisk guide ↓

Your soul is orange · Bravery

Go as Undyne

Bravery acts before the fear finishes its sentence. Undyne suplexes a boulder because it is in the way. That is your scoring, in armor.

Red ponytail, black eyepatch, dark armor or tank top, a spear.

Full Undyne guide ↓

Your soul is yellow · Justice

Go as Sans

Justice keeps score. Sans looks lazy, but he remembers every choice you made and hands down the verdict. A yellow soul does the same.

Blue hoodie, white tee, black shorts with a white stripe, pink slippers.

Full Sans guide ↓

Your soul is green · Kindness

Go as Toriel

Kindness protects even when it hurts. Toriel would rather fight you than let you walk into danger. That is the green soul's exact shape.

Long purple robe with the white Delta Rune, goat ears and small horns, a pie.

Full Toriel guide ↓

Your soul is light blue · Patience

Go as Napstablook

Patience is power on standby. Napstablook never rushes anything, not the fight and not the feelings, and neither does your spread.

A white sheet, two eye holes, a pair of headphones.

Full Napstablook guide ↓

Your soul is blue · Integrity

Go as Papyrus

Integrity keeps its word even to an enemy. Papyrus promises a capture, delivers a capture, and cannot bring himself to hurt anyone.

White chest armor with an orange emblem, red scarf, red gloves and boots.

Full Papyrus guide ↓

Your soul is purple · Perseverance

Go as Alphys

Perseverance keeps working after the worst mistake. Alphys' lab is a monument to trying again. The purple soul's whole story.

White lab coat, round glasses, yellow top, a clipboard.

Full Alphys guide ↓

Already picked? The full costume guides.

Each guide has a cheap version you can build tonight and a better version for people who want to be recognized from the far side of the party. The one detail that sells it is the part to spend your effort on if you only have time for one thing.

Determination · red

Frisk

Reads instantly because: Two pink stripes on a blue shirt. That is the whole silhouette, and anyone who has seen the game recognizes it from across a room.
Wear: A blue long-sleeve shirt or sweatshirt with two magenta stripes across the chest, blue shorts, brown shoes, and straight brown hair with bangs (a bob wig if yours isn't).
The cheap version: A plain blue sweatshirt, a roll of duct tape as masking, one tube of magenta fabric paint. Tape two bands, sponge the paint on, peel. Under $15 and one evening.
The better version: A knit sweater in the exact blue and magenta, a brown bob wig, and a wooden stick with a bandage wrapped around one end, which is the first weapon in the game.
The one detail that sells it: The blank face. Frisk never emotes. Keep your expression flat in every photo and the costume works twice as hard.
Where it photographs best: Standing still in a doorway or at the top of a staircase, stick held loosely, looking straight at the camera. Bring a Chara for the mirror shot.

Bravery · orange

Undyne

Reads instantly because: The red ponytail and the eyepatch. Everything else is armor detail; those two carry it.
Wear: A long red ponytail (wig, or spray and tie), a black eyepatch over the left eye, a black tank top or dark armor over blue skin, dark trousers, boots, and a spear.
The cheap version: Black tank, black leggings, a $5 eyepatch, a red wig. Skip the blue body paint and wear a blue hoodie under the tank instead; from a distance it still reads.
The better version: Blue face and arm paint (water-activated, not grease), a craft-foam chest plate painted gunmetal with silver trim, and a spear built from a broom handle and a foam head wrapped in cyan tape.
The one detail that sells it: The teeth. Undyne grins with a mouth full of fangs. Yellow fang tips or a wide painted grin, and the fiercer the better.
Where it photographs best: Mid-lunge, spear forward, one leg back, shouting. Undyne does not stand still in photos.

Justice · yellow

Sans

Reads instantly because: Blue hoodie, pink slippers, permanent grin. It is the most photographed Undertale costume every October for a reason: three items and done.
Wear: A blue zip hoodie with the hood up, a white T-shirt, black shorts with a white stripe down each side, pink slippers, and a skull face.
The cheap version: Any blue hoodie, black shorts with white tape stripes, pink slippers from the pharmacy aisle, white face paint with black eye sockets. Under $20.
The better version: A foam or papier-mâché skull mask with a cut-out for one glowing blue eye (a blue LED behind cellophane), a fleece-lined blue hoodie, and real slippers.
The one detail that sells it: The left eye. Blue glow, right socket dark. It is the single image the internet remembers of him, so get that one thing right.
Where it photographs best: Hands in the hoodie pockets, slouched, half-turned to the camera. The lazier the pose, the better the Sans.

Kindness · green

Toriel

Reads instantly because: The purple robe with the white winged symbol, and the soft white ears. Warm and immediately parental.
Wear: A long purple robe or dress with the Delta Rune (a winged circle above three triangles) in white on the chest, white goat ears and short horns on a headband, white gloves.
The cheap version: A purple graduation gown or a purple bedsheet tunic, the rune cut from white felt and glued on, ears cut from white felt on a headband.
The better version: A tailored purple robe with white trim, a proper goat-ear headband with small horns, white fur cuffs, and a butterscotch-cinnamon pie. A real pie wins every party.
The one detail that sells it: The rune. Draw it right, a circle with two wings above three small triangles, and everyone knows exactly who you are.
Where it photographs best: Offering the pie to the camera, or kneeling to a Frisk's eye level. She is the warmest character in the game; play it.

Patience · light blue

Napstablook

Reads instantly because: A ghost wearing headphones. It costs less than the candy you will collect.
Wear: A white sheet with two eye holes and a small mouth cut out, and a pair of over-ear headphones on top.
The cheap version: The sheet. The headphones you already own. Total cost: zero.
The better version: A hemmed white sheet with a weighted edge so it doesn't ride up, black felt eyes stitched on instead of cut out, and a small speaker under the sheet playing quiet lo-fi.
The one detail that sells it: The mood. Napstablook is shy, sad, and apologizes for existing. Speak quietly, drift into corners, say "oh... sorry."
Where it photographs best: Lying flat on the floor at the party. It is Napstablook's signature move, and it photographs perfectly from above.

Integrity · blue

Papyrus

Reads instantly because: The red scarf and the big white battle body. Tall, loud, and completely sincere.
Wear: White chest armor with an orange emblem, a red scarf long enough to move, red gloves, blue shorts with a gold belt, tall red boots, and a skull face.
The cheap version: A white T-shirt with cardboard shoulder pads taped underneath, a red thrift-store scarf, red gloves, blue shorts with a gold tape waistband, red rain boots, white face paint.
The better version: Football shoulder pads wrapped in white cloth and white tape, the orange emblem cut from craft foam, a papier-mâché skull with a fixed toothy grin, knee-high red boots.
The one detail that sells it: The posture. Chest out, fists on hips, chin up. Papyrus believes in himself completely, and the costume only works if you do too.
Where it photographs best: A heroic stance one step above everyone else, scarf caught in a breeze (or held out of frame by a friend). "Nyeh heh heh" optional but recommended.

Perseverance · purple

Alphys

Reads instantly because: Big round glasses, a lab coat, yellow scales. The nervous scientist, instantly.
Wear: A white lab coat, round black-frame glasses, a yellow top and leggings (or yellow face and hand paint), buck teeth, and a small tail.
The cheap version: A white shirt worn open as a lab coat, any round glasses, a yellow hoodie. The glasses do most of the work.
The better version: A real lab coat, yellow scale makeup, a foam tail and back spikes, a clipboard covered in anime stickers, and an ID badge that reads Royal Scientist.
The one detail that sells it: The nervous energy. Stammer, push the glasses up, hold the clipboard like a shield. Alphys is anxiety in a lab coat, lovingly.
Where it photographs best: Peeking around a corner or from behind the clipboard. Bring an Undyne and let the fandom do the rest.

Four more the party expects

Not tied to a soul color, but if you are going as a pair or a group, these are the ones people ask for.

Chara Frisk's mirror: a green sweater with one yellow stripe, brown shorts, rosy cheeks, and a toy knife. Go as a pair with a Frisk.
Flowey Yellow petals on a headband framing your face, a green hoodie, and a flowerpot to carry or stand in. Smile a little too wide.
Mettaton EX Thigh-high pink boots, a black leotard, one shoulder pad, magenta hair swept over one eye. The most glamorous thing in the Underground.
Asgore A purple cape over gold armor, a big white beard, horns, and a red trident. Toriel's counterpart; go as a pair.

Still deciding?

The quiz settles it in eight minutes, and the result card is built to be shared: your seven scores, your character, and the reason.

♥ Take the quiz

Want the lore first? What the seven soul colors mean · Undertale explained in two minutes

Questions

Which Undertale character should I be for Halloween?

If you know which of the seven soul colors is yours, use the table above: each color has one character whose personality matches it. If you don't, the 66-question Soul Virtues quiz on this site scores all seven virtues and tells you the top one in about eight minutes.

What is the easiest Undertale Halloween costume?

Napstablook: a white sheet, two eye holes and a pair of headphones. After that, Sans (a blue hoodie, black shorts and pink slippers) and Frisk (a blue shirt with two pink stripes). All three can be put together in one evening from things most people already own.

Can we do an Undertale group costume?

Yes, and the pairs are built in: Frisk and Chara, Toriel and Asgore, Sans and Papyrus, Undyne and Alphys. A group of seven can go as the seven souls themselves, each in one color with a heart on the chest.

Do I need to have played Undertale to use this?

No. Every guide starts with one line about who the character is, and the quiz asks about everyday choices, not game knowledge. Undertale © Toby Fox; this is an unofficial fan site.