If you are reading this Undertale pacifist route guide, you probably already know that Undertale is not your typical RPG. You do not have to kill a single monster to reach the end. In fact, the game rewards you for showing mercy at every turn. The True Pacifist ending is widely considered the best and most complete way to experience the story, and our team has put together this guide to walk you through every single step.
This guide covers the entire pacifist run from start to finish. You will learn how to spare every boss, befriend every key character, unlock the hidden True Lab, and earn the True Pacifist ending. Whether you are a first-time player or someone who got a Neutral ending and wants to see what you missed, we have you covered.
One important note before we start: you cannot get the True Pacifist ending on your very first playthrough without completing a Neutral run first. Do not worry if this sounds confusing. We explain exactly how that works in the Requirements section below.
Table of Contents
What Is the True Pacifist Route in Undertale?
The True Pacifist route is Undertale’s happiest and most complete ending. To achieve it, you must go through the entire game without killing a single monster, and you must also befriend three key characters: Papyrus, Undyne, and Alphys. This is different from a regular pacifist run, where you might spare every monster but miss the friendship events.
A regular pacifist run where you spare everyone but skip the friendship events leads to a Neutral ending called the “Flawed Pacifist” ending. The distinction matters because only the True Pacifist route unlocks the full story, including the True Lab area and the final boss fight with Asriel Dreemurr.
Many players on Reddit and gaming forums describe the True Pacifist ending as the “real” ending of Undertale. It reveals the full backstory, resolves character arcs, and shows monsters being freed from the Underground. If you want the complete Undertale experience, this is the route to take.
Undertale Pacifist Route Guide: Requirements for True Pacifist
Before starting your True Pacifist run, you need to understand every requirement. Missing even one step can lock you into the Neutral ending. Here is the complete checklist for unlocking the True Pacifist ending in 2026:
- Spare every monster in the game. This includes all random encounters and all boss fights. If you kill even one monster, you are locked out of True Pacifist for that run. Check your stats in the menu. Your kill count must stay at zero.
- Spare Toriel in the Ruins. This is the first major test. Toriel will attack you, and you must choose to SPARE her repeatedly. She will eventually stop fighting.
- Complete a Neutral route first. On your first playthrough, you will fight Asgore and Flowey no matter what. After completing the Neutral ending and getting the phone call from Flowey, reload your save to continue toward True Pacifist.
- Befriend Papyrus. After defeating Papyrus in Snowdin, go back to his house. Talk to him to trigger the date event. Complete the entire date sequence.
- Befriend Undyne. After the Undyne fight in Waterfall, travel to Hotland. You will find Undyne collapsed on the ground from the heat. Pour water on her using the water cooler nearby. Later, visit her house in Waterfall and complete the hangout event.
- Deliver Undyne’s letter to Alphys. After befriending Undyne, she will give you a letter. Take it to Alphys’s lab in Hotland. This triggers a date event with Alphys.
- Complete the True Lab. After the Alphys date, the True Lab becomes accessible in Alphys’s bathroom. Explore the entire lab and reach the end to complete this requirement.
If you have already completed a Neutral run on your current save file, you can skip straight to the friendship events after reloading. You do not need to replay the entire game from scratch. Just go back and complete the befriendship events you missed.
Can you get True Pacifist on your very first run? Technically yes, but it requires you to have never completed any route before. Even then, the game forces you through the Neutral ending fight with Asgore and Flowey first. After that fight, Flowey tells you what to do next, and you can reload your save to pursue True Pacifist.
Step-by-Step Walkthrough – The Ruins
The Ruins are the first area in the game and where you learn the core mechanic that defines your entire pacifist run: the SPARE command. Every time you enter a battle, you can choose ACT to interact with the monster, then choose SPARE when their name turns yellow. That yellow name is your signal that the monster no longer wants to fight.
Your first real test is the dummy encounter at the start of the Ruins. Toriel sets this up as a tutorial. You can attack or spare the dummy. Either choice works for the pacifist route since the dummy is not a real monster. However, attacking the dummy is fine and does not count as a kill.
After the dummy, you will encounter real monsters like Froggit, Whimsun, and Moldsmal. Each one has a specific ACT command that makes them spareable. For Froggit, use the “Compliment” ACT. For Whimsun, just pick “Console” or wait a turn and they will flee on their own. Moldsmal can be spared immediately since it is passive.
How to Spare Toriel
Toriel is the first boss and the first moment where many new players accidentally kill a monster. She blocks your path at the exit of the Ruins. When you try to SPARE her, the option will be crossed out at first. Many players assume they have to fight her.
Do not attack Toriel. Keep choosing SPARE even when it seems like nothing is happening. After several turns of choosing SPARE, Toriel will stop attacking and let you pass. Her fire attacks become easy to dodge if you stay near the center of the arena. Just move in small adjustments rather than large sweeps.
If you do accidentally kill Toriel, you can reset the game immediately and try again. The game remembers your choices within the current session, so a full restart is your best option here.
Step-by-Step Walkthrough – Snowdin (Befriending Papyrus)
Snowdin is the second area and home to one of the most memorable characters in the game: Papyrus. This area introduces ice physics, new monsters, and the first required friendship event for your True Pacifist run.
Random encounters in Snowdin include monsters like Snowdrake, Ice Cap, and Gyftrot. For Snowdrake, use the “Laugh” ACT to make him spareable. For Ice Cap, use “Steal” to take his hat, then spare him, or use “Ignore” twice. Gyftrot requires you to “Undecorate” him by removing all the decorations that other monsters put on his antlers.
Fighting and Befriending Papyrus
Papyrus attacks you at the end of Snowdin. His bone attacks come in patterns that require precise jumping. The blue bones are the tricky ones. When a blue bone passes through you, do not move. Stay completely still. Blue attacks only hurt you if you are moving.
Once you survive enough turns, Papyrus will offer to spare you. Accept his offer. After the fight, he lets you pass. But for the True Pacifist route, sparing him is only the first step. You must also befriend him.
Return to Snowdin Village and go to Papyrus’s house. Talk to him to start the date event. During the date, choose dialogue options that are supportive and encouraging. The date is mostly linear, so just follow along and be nice to Papyrus. Complete the entire sequence until he gives you his phone number and you return outside.
This friendship event is mandatory for the True Pacifist ending. If you skip it, you will be locked out of the True Pacifist route even if you spare every monster. I have seen players on Reddit report getting a Neutral ending specifically because they forgot to go back and do the Papyrus date.
Step-by-Step Walkthrough – Waterfall (Befriending Undyne)
Waterfall is where the pacifist run starts to demand more patience. This area features tougher monsters and two tricky boss encounters. It is also where you start working toward befriending Undyne, which is one of the most commonly missed requirements in the entire game.
Random encounters in Waterfall include Aaron, Woshua, and Shyren. For Aaron, keep “Flexing” at him until he gets tired of flexing and leaves. For Woshua, let him wash you by choosing “Clean” and then spare him. Shyren can be spared by humming to her repeatedly, which builds a mini-concert.
How to Spare Undyne
Undyne chases you through Waterfall in a sequence of intense encounters. During the first encounter at the foggy bridge, you must flee from her. During the actual boss fight in her house, you cannot damage Undyne. Your goal is to survive.
Dodge her spear attacks by moving carefully. The green SOUL mode forces you to hold a shield and block spears from specific directions. Block spears coming from the direction indicated by the arrow. After enough turns, the fight transitions and Undyne collapses from exhaustion.
Choose to pour water on her when she passes out. If you do not have water, head to Hotland and come back. But the most reliable method is to get water from the water cooler near the Hotland entrance right after she collapses there.
The Undyne Hangout Event
After giving Undyne water in Hotland, go back to her house in Waterfall. Talk to her to start the hangout event. During this sequence, Undyne will challenge you to a cooking lesson, then a fake fight, and finally a friendship moment. Complete the entire event.
The hangout ends with Undyne acknowledging you as a friend. This is another mandatory event for True Pacifist. Without it, the letter delivery to Alphys never triggers, and you cannot access the True Lab.
Many players get confused about the timing here. You must first give Undyne water in Hotland, and then visit her house in Waterfall. If you skip the water step, she will not be available for the hangout. This is one of the most common mistakes players report on forums.
Step-by-Step Walkthrough – Hotland and CORE
Hotland and the CORE are the longest sections of the game and contain some of the trickiest encounters for a pacifist run. This is where players face Muffet, Mad Dummy, and Mettaton EX. Each of these encounters requires a specific strategy to spare.
Random encounters in Hotland include Vulkin, Tsunderplane, and Pyrope. Vulkin can be encouraged or discouraged. Either “Encourage” or “Heckle” works, but encouraging is the kinder option. Tsunderplane requires you to “Approach” then back off, mimicking a tsundere dynamic. Pyrope just needs you to “Heatsnug” twice.
How to Spare Muffet Without Killing Her
Muffet is a spider monster who attacks you because she thinks you hate spiders. Her fight involves dodging web patterns and cupcakes. The key to sparing Muffet is surviving long enough. If you bought a Spider Donut or Spider Cider from the Spider Bake Sale earlier in the game, use it during the fight. Muffet recognizes the purchase and lets you go.
If you did not buy a spider item, you need to survive her attacks for about 17 turns. Eventually, she receives a telegram from the spiders confirming you are not anti-spider, and she spares you. This is the longer route but it works.
How to Spare Mad Dummy
Mad Dummy is immune to your ACT commands. You cannot spare him directly. Instead, you must dodge his magic cotton attacks and trick his dummy minions into hitting him with their own attacks. Cry during the fight to make his magic cotton attacks appear. Guide those cotton balls into Mad Dummy to whittle him down.
Eventually, Napstablook shows up and scares Mad Dummy away. This encounter resolves itself if you survive long enough. Just keep dodging and crying, and the fight will end on its own.
Mettaton EX Ratings Guide
Mettaton EX is the boss of the CORE, and sparing him works differently from other fights. Instead of using the SPARE command, you need to raise the television ratings above 10,000. The fight is a live TV show, and high ratings make Mettaton happy.
To boost ratings quickly, use these ACT commands: “Pose” when your SOUL is yellow, “Heel Turn” during certain phases, and equip the GlowShades or other flashy items before the fight. Each pose and action adds to your ratings counter. Once you hit 10,000, Mettaton stops fighting and the broadcast ends.
For the highest ratings, try to vary your actions. Using the same move repeatedly gives diminishing returns. Mix up poses, throw the disco ball, and let Mettaton’s attacks graze you for bonus drama points. Ratings above 12,000 unlock extra dialogue.
New Home – Asgore and the Neutral Completion
New Home is the final area of the main game and the location of the Asgore fight. On your first playthrough, this fight is unavoidable and ends the game with a Neutral ending. This is normal and expected. Even if you have spared every monster up to this point, the game requires you to go through this encounter once.
How to Spare Asgore
The Asgore fight is intense because he destroys the MERCY button at the start of the battle. You literally cannot press SPARE. Your only option at first is to fight back. Reduce his health to a sliver. When his health is nearly gone, the SPARE option appears. Choose it immediately.
After you spare Asgore, Flowey intervenes and steals the human SOULs. This leads to the Photoshop Flowey fight. Defeat Photoshop Flowey by surviving his attacks and calling for help from the stolen SOULs. Each SOUL you free weakens him.
Once Photoshop Flowey is defeated, he will talk to you. If this is your first time completing the game, Flowey tells you about the friendship requirements and suggests you go back and complete them. After this conversation, the game ends with a Neutral ending. Reload your save file to continue toward True Pacifist.
Delivering the Letter and the Alphys Date
After completing the Neutral route and reloading your save, your next goal is to deliver Undyne’s letter to Alphys. If you have already befriended Papyrus and Undyne, Undyne will call you and ask you to deliver a letter to Alphys’s lab.
Head to Alphys’s lab in Hotland. She is not there when you arrive, but slide the letter under the door. Alphys reads the letter, which she mistakes for a love letter from you. This triggers the Alphys date event.
During the date, Alphys takes you to the dump in Waterfall. Follow the dialogue and be supportive. Eventually, the date takes a turn when it becomes clear Alphys has feelings for someone else. Be kind and understanding throughout the conversation. The date ends with Alphys feeling embarrassed but grateful.
After the date, Undyne shows up and the two of them talk. This resolves the Alphys friendship event. But there is one more step. Head back to Alphys’s lab. The bathroom door, which was previously locked, now opens into the True Lab.
True Lab Walkthrough
The True Lab is a hidden area beneath Alphys’s lab and the final major requirement for the True Pacifist ending. It is darker and more unsettling than the rest of the game. You will encounter amalgamates, which are fused monsters created by Alphys’s experiments with determination.
How to Access the True Lab
Enter through the bathroom in Alphys’s lab after completing the Alphys date event. The elevator takes you down to the True Lab. Once you enter, the elevator malfunctions, and you must explore the lab to find a way back up.
Key Locations and Progression
The True Lab has several rooms you need to explore in order. In the first room, read the entries on the computer monitors. These explain Alphys’s experiments and provide lore context. Move through the hallway and enter each side room.
You will need to find four keys scattered across the lab. Each key unlocks a door to the next area. The keys are found in refrigerators, computer terminals, and hidden corners of rooms. Explore every room thoroughly and interact with everything.
Amalgamate Encounters
The amalgamates cannot be killed. Your goal is to spare them or survive their encounters. Each amalgamate has a specific ACT command. For Endogeny, “Recoil” and “Pet” work. For Snowdrake’s Mother, “Talk” and “Joke” are the right choices. For Lemon Bread, “Unhug” and then “Talk” resolve the encounter. For Reaper Bird, “Plead” works.
These encounters can be tense because the amalgamates hit hard. Bring plenty of healing items. The Sea Tea and Instant Noodles are good options if you have them. Stay patient and keep using the correct ACT commands.
Completing the True Lab
After finding all keys and exploring every room, return to the power room. Turn on the main power to restore the elevator. Before you leave, all the amalgamates appear and have a brief moment of reconciliation with Alphys. This is one of the most emotional scenes in the game.
Ride the elevator back up to the lab. This completes the True Lab section and triggers the final sequence of the True Pacifist route.
Final Battle – Asriel Dreemurr
The final boss of the True Pacifist route is Asriel Dreemurr. This fight is unique because you cannot lose. If your health reaches zero, you refuse to give up and continue fighting. The mechanics of this battle are about saving your friends, not defeating Asriel.
Asriel Fight Mechanics
Asriel uses two powerful attacks. The first is a star-shaped projectile pattern during his initial phase. Dodge these by moving through the gaps. The second is the “Hyper Goner” attack, which creates a massive suction effect. Move against the pull and dodge the incoming projectiles.
During the fight, you have access to specific ACT commands. Choose “Hope” to reduce damage, and choose “Dream” to heal yourself. These replace your normal item options.
Saving Your Friends
The key to winning this fight is saving your friends. Use the ACT command to interact with the lost SOULs of your friends one by one. Each friend has specific memories you need to call out to bring them back.
For Toriel, call out memories of her caring for you. For Papyrus, reference his puzzles and his desire to be popular. For Undyne, remind her of her strength and her friendship. For Alphys, speak about her kindness and her favorite shows. Each friend you save weakens Asriel’s attack patterns.
Once all friends are saved, Asriel transforms into his final form. Continue to choose “SAVE” and then select “Asriel Dreemurr.” This triggers the final scene where Asriel is saved and the barrier is broken. The game transitions into the epilogue and the True Pacifist ending plays out.
Common Mistakes That Lock You Out of True Pacifist
Our team has read through hundreds of forum posts from players who accidentally locked themselves out of the True Pacifist ending. Here are the most common mistakes and how to avoid them in 2026.
Killing a random encounter monster. This is the most common mistake. If you kill even one monster, you cannot get True Pacifist. Always choose ACT first to figure out how to spare the monster, then choose SPARE when the name turns yellow. If you are unsure, run away using the FLEE option. Fleeing does not count as killing.
Missing Undyne’s water moment. After the Undyne fight in Waterfall, she chases you into Hotland and collapses from the heat. You must go to the nearby water cooler, get a cup of water, and pour it on her. If you walk past without doing this, the hangout event never triggers. You can reload a save and try again if you missed it.
Skipping the Papyrus date. After beating Papyrus, the game lets you continue without going back to his house. But you must go back and complete the date event. It is easy to miss because nothing forces you to return to Snowdin.
Not delivering Undyne’s letter. After befriending Undyne, she gives you a letter for Alphys. If you head straight to New Home without delivering it, you miss the Alphys date and True Lab entirely.
Getting a Neutral ending and thinking you failed. On your first playthrough, you will get a Neutral ending even if you spare everyone. This is not a failure. Reload your save and complete the friendship events to continue toward True Pacifist.
What resets fix. A normal reset from the menu preserves certain data. A True Reset from the game’s ending screen clears everything. If you accidentally killed a monster, a normal reset lets you try that section again. A True Reset is a full restart.
Frequently Asked Questions
How do I do the True Pacifist Route in Undertale?
To complete the True Pacifist Route, spare every monster in the game, befriend Papyrus by completing his date event in Snowdin, give Undyne water when she collapses in Hotland and complete her hangout event, deliver Undyne’s letter to Alphys and complete the date, then explore the True Lab beneath Alphys’s lab. You must first complete a Neutral route before the friendship events become available.
How do you beat Muffet without killing her?
You can spare Muffet by either using a Spider Donut or Spider Cider during the fight (purchased from the Spider Bake Sale in the Ruins or Hotland), which she recognizes and lets you go immediately. If you do not have a spider item, survive her attacks for about 17 turns until she receives a spider telegram confirming you are not hostile to spiders.
Does killing So Sorry ruin pacifists?
Yes, killing So Sorry counts as killing a monster and will lock you out of the True Pacifist ending for that run. So Sorry is an optional hidden encounter found by reading the sign in the Hotland art room on specific dates. Since the encounter is optional, you can simply avoid it entirely if you are concerned about the fight.
What does 16 left mean in Undertale?
The ’16 left’ message appears during the Mettaton EX fight and refers to the viewer count or ratings countdown. It is part of the television broadcast mechanics of that encounter. The number decreases based on your performance, and your goal is to reach a high enough rating before the show ends. Focus on posing, using varied ACT commands, and keeping the ratings above 10,000 to spare Mettaton.
How to get true pacifist ending first run?
You cannot get the True Pacifist ending on your very first playthrough without first completing a Neutral run. The game forces you through the Asgore and Flowey fights before making the friendship events available. However, you can achieve it in a single continuous playthrough by sparing everyone during your first run, then reloading your save after the Neutral ending and completing all the friendship events without starting over from scratch.
What is the difference between Pacifist and True Pacifist?
A regular Pacifist run means sparing every monster without killing anyone. A True Pacifist run includes sparing everyone plus befriending Papyrus, Undyne, and Alphys through their date and hangout events. Regular Pacifist without the friendship events leads to a Neutral ending called the Flawed Pacifist ending. True Pacifist unlocks the True Lab, the Asriel boss fight, and the ending where monsters are freed from the Underground.
Conclusion
This Undertale pacifist route guide covers every step you need to earn the True Pacifist ending, from your first encounter in the Ruins to the final battle with Asriel Dreemurr. The path is straightforward once you understand the requirements: spare every monster, befriend Papyrus, Undyne, and Alphys, and explore the True Lab.
The biggest takeaway I want you to remember is that the True Pacifist route requires patience. You will not get it on your first pass through the game. The Neutral ending is a required stepping stone. After completing it, reload your save and focus on the friendship events you missed. The game literally tells you this through Flowey’s dialogue at the end of the Neutral route.
For first-time players, I recommend playing the game naturally on your first run without worrying too much about the perfect route. Try to spare monsters when you can, but do not stress if something goes wrong. You can always reload a save or reset. The journey through Undertale is about the experience, not just the ending.
One thing worth mentioning is the Soulless Pacifist ending. If you complete a Genocide route and then do a True Pacifist run, the ending changes slightly. Without spoiling too much, the final scene has a darker tone. This is permanent for that save file unless you wipe the game’s hidden data. Most players recommend doing True Pacifist before Genocide to experience the happy ending first.
After completing True Pacifist, you can use the True Reset option to start a completely fresh playthrough. This clears all progress and lets you experience the game from scratch. Some players enjoy doing multiple runs to see how the story changes with different choices.
The True Pacifist route is absolutely worth the effort. It delivers the most complete version of Undertale’s story, reveals the full depth of its characters, and ends with one of the most satisfying conclusions in gaming. Grab some Spider Donuts for Muffet, keep a cup of water handy for Undyne, and enjoy the journey.