UNDERTALE Fight Guide: Getting started
About
OverviewUNDERTALE Fight! is a Roblox battle game set in the worlds of UNDERTALE, DELTARUNE, and fan games, putting you up against more than 50 bosses and monsters including Sans, Undyne, Papyrus, Mettaton, and Jevil. You earn G through combat, climb the ranks, and unlock increasingly powerful characters. This guide covers how to get started, how to earn G efficiently, how to play Sans and Papyrus, and how to work toward the game's badges.
What is on this page
Contents
Getting started
Step
When you join for the first time the game walks you straight into a tutorial. Complete it to earn the WELCOME TO THE UNDERGROUND badge. After that, jump into a real fight — your first victory hands you the DETERMINATION badge.
- Finish the tutorial the WELCOME TO THE UNDERGROUND badge confirms you have the basics down.
- Win your first fight the DETERMINATION badge unlocks once you pull through.
- Lose once falling in battle for the first time gives you the GAME OVER badge.
- Invite a friend winning a fight while in a party earns you STRONGER TOGETHER.
- Set an early G target 10,000 G is your first milestone and earns the TEM COLLEGE FUND badge.
MetaNew Player Survey
The next survey is being prepared.
Game modes
Tips
The game offers several distinct modes.
- Endless mode — survive waves to earn badges: wave 10 gives KEEP GOING!, wave 25 gives IT NEVER ENDS.
- Daily Challenge — a mode with conditions that change every day.
- 1v1 — a straight duel against one other player.
- Party mode — team up with friends and fight together; winning earns STRONGER TOGETHER.
- Boss Editor — lets you create custom bosses.
- Roll for rare SOUL skins and show them off.
Playing Sans
TipsSans is available at Rank 3. He has three upgrades. His second upgrade lets him sell hotdogs from a cart, healing allied monsters and earning G at the same time. His third upgrade, The Judge, adds the PRESSURE passive: cooldowns shrink as his stamina drops. At 30 stamina his eye glows blue and yellow.
- Land BALLING or TROMBONE first, then immediately follow up with second-type Bone Throw.
- In The Judge upgrade, use TELEKINESIS to launch an enemy upward, then fire Gaster Blasters into them while they are airborne.
- Activate get dunked on when an enemy is about to hit you — any hit during its duration sends them flying and fires massive Gaster Blasters at them.
- The hotdog cart in the second upgrade heals teammates and adds G to your total each time another player buys one; KOBK players can also buy and eat the hotdogs.
- Type 2 Fast Travel in upgrades 0–2 lets you ride a tricycle at speed 35 and use other moves while on it.
- KOBK players who touch the Whoopee Cushion from TROMBONE are sent flying and ragdolled for a short while.
Playing Papyrus
Tips
Papyrus starts at Rank 1. His first upgrade raises his defense from 10 to 20. His second upgrade, New Cool Moves, replaces his basic bone attacks with stronger versions. His third upgrade, Fulfilled Greatness, changes his appearance and adds further moves.
- Great Leap creates a large bone circle on takeoff and again on landing.
- Special Attack floods the area with blue bone sliders that ragdoll any KOBK player who moves through them.
- After getting New Cool Moves, Cool Bone locks onto a specific player and follows them.
- Bone Trap from the New Cool Moves upgrade sits on the ground and can only be used once but can be retrieved.
Earning G
CheckG is the game's currency, earned through combat. The badge milestones are 10,000 G (TEM COLLEGE FUND), 1,000,000 G (MILLIONAIRE), and 10,000,000 G (HEART OF GOLD).
- Play in Party mode co-op sessions give you badge progress and combat time at once.
- Prestige at least once your first prestige earns the RESET badge.
- Sell hotdogs as Sans (second upgrade) each purchase by another player adds G directly to your total.
HALLOWEENPART2
BOSSMAKER
FLOWERKING
HALLOWEEN2026
Pacifist and genocide badge paths
WarnThe TRUE PACIFIST badge requires you to spare every monster at least once. The LOVE badge triggers the first time you kill a monster — LOVE stands for Level Of ViolencE.
Community strategy ideas
CommunityThese ideas and tips come from people playing the game. Share your discoveries too!
No strategy ideas yet. Share a tip you discovered.
Share a strategy idea
[SOON] UNDERTALE Fight!
Glossary
Glossary- G
- The game's currency, short for Gold, earned by fighting.
- KOBK
- Short for Kill or Be Killed.
- Stamina
- The resource Sans uses instead of HP; reaching zero makes him unable to act.
- PRESSURE
- Sans's passive ability in The Judge upgrade that shortens move cooldowns as his stamina falls.
- Rank
- A number you must reach before a character becomes available to play.
- Prestige
- Resetting your progress, rewarding you with the RESET badge on your first attempt.
- Spare
- Choosing to let a monster live rather than defeat it, which is required for pacifist badges.
- SOUL skin
- A cosmetic item obtained by rolling.
Common questions
FAQWhere does the tutorial start?
The game guides you into the tutorial automatically when you join. Finishing it earns the WELCOME TO THE UNDERGROUND badge.
What rank do I need for Sans and Genocide Run Sans?
Regular Sans is available at Rank 3. Genocide Run Sans requires Rank 40, but owning the Extra Characters Gamepass drops that requirement to Rank 1.
How do I earn badges in Endless mode?
Surviving to wave 10 earns KEEP GOING! and surviving to wave 25 earns IT NEVER ENDS.
Can enemies also use items meant for my team?
Yes — when Sans sets up his hotdog cart in his second upgrade, KOBK players can buy and eat the hotdogs too.
Do I have to choose between a pacifist and a genocide run permanently?
No. The TRUE PACIFIST badge only needs you to spare every monster at least once across your playtime, and kill-based badges like LOVE can be earned in separate sessions.
Game updates can change what is on this page. If you spot something, get in touch and let us know.
