After naming the fallen human, players have a choice of choosing between three major routes in the game. Before we dive right in, I'd like to add that SPOILERS (and spoilers) WILL BE EVERYWHERE. Now let's begin.

The Neutral Route is the first and most important route in the game. It’s the default path, where the you neither fully befriend nor fully harm anyone. The Neutral Route is triggered when the conditions for the other two routes are not met, or if you on your first playthrough did not kill anyone as access to one of them.

The final boss of the Neutral Route is Flowey. After a battle with Flowey, you have the option to face off against ASGORE once again. However, Flowey will intervene and kill ASGORE, causing the fight with him to be skipped.

Sans will call your cell phone and leave a message detailing the fate of the Underground in all versions of this ending. The content of his message will vary depending on your actions throughout the game. Whether you befriended monsters, showed mercy, or caused harm will influence what Sans says.

Note: As this is the most important part of the game and has arguably the most impact, ending cutscenes will be spoiler-texted.

Main Requirement: Spare Toriel.

Spoiler Cutscene: Toriel returns to her throne and resumes ruling over the Underground. She enforces a policy of non-hostility toward future humans who fall into the Underground.

This ending can branch into one of three variations: the "Flawed Pacifist Ending," the "Betrayed Undyne Ending," or the "Exiled Queen Ending."


First branch requirements: Befriend Papyrus, Undyne and don't kill any monsters.
Second branch requirements: Befriend Papyrus, Undyne, Alphys and don't kill any monsters.

Spoiler Cutscene: After Sans' dialogue, the call switches to Papyrus, who proclaims himself "CAPTAIN OF THE ROYAL GUARD." However, this position is a figurehead since the Royal Guard has been disbanded. His primary duty is tending to the garden at the New Home castle. Undyne then joins the conversation, explaining she has taken a new role as Alphys's lab assistant. She expresses grief over the loss of Asgore but reassures that you're not to blame because you just did what was necessary. The next part of the call varies based on whether you have dated Alphys.

• If you have not dated Alphys: Undyne mentions that Alphys has become more reclusive, and she also reminds you that the monsters sacrificed a great deal to help you return to the human world. She urges you to appreciate life on the Surface and honor that sacrifice.
  
  
• If you have dated Alphys: Alphys joins the call and reveals she is working tirelessly to find a way to free the monsters from the Underground. Toriel is a much stricter supervisor than Asgore ever was, making Alphys work harder than before.

The call ends with Sans mentioning that the phone is low on battery, and everyone says their goodbyes.


First branch requirements: Befriend Papyrus and spare Mettaton.
Second branch requirements: Befriend Papyrus, Undyne and kill Mettaton.
Third branch requirements: After befriending Papyrus and Undyne, kill 1-9 non-boss monsters.

Spoiler Cutscene: The call starts like the Family Ending, but soon after, Sans hands the phone to Papyrus, who takes over the conversation. The next part branches based on your actions:

If you have not befriended Undyne but spared Mettaton: Undyne blames you for Asgore's death. Papyrus mentions that Undyne is planning to cross the barrier and take revenge on you. He urges you to keep in touch to make their plans easier.

If you killed Mettaton: Undyne is devastated by the loss of both Asgore and Alphys, who has gone missing. Papyrus is unaware of what happened to Asgore or Alphys and asks you to "bring Undyne's friends back," as she is struggling without them.

If you befriended Undyne but killed monsters afterward: Undyne (rightfully) hates herself and expresses regret for becoming friends with you, as you soon killed someone after she trusted you. Papyrus says that you should "PROBABLY NEVER COME BACK HERE" and warns that Undyne would definitely destroy you if you do and not even Toriel could stop her.

The call ends with Papyrus saying goodbye (forever, if in the third branch).


First branch requirements: Kill Undyne, 10 or more non-boss monsters, and spare Papyrus.
Second branch requirements: Kill Papyrus, 10 or more non-boss monsters, and spare Undyne.

If Papyrus is alive and Undyne is dead: Toriel peacefully resigns and returns to the Ruins after hearing about the rebellion. This leaves the Underground in a state of anarchy. Papyrus, however, stays with Toriel and enjoys playing games with her. He expresses his desire to "stand in for the Queen" and practices becoming a "GREAT MOM" for when you return someday. The call ends with Sans expressing hope that things are better where you are.

If Undyne is alive and Papyrus is dead: Undyne is enraged over Asgore’s death, leads a revolution and exiles Toriel back into the Ruins, assuming the role of empress of the Underground. Sans stays with Toriel in the Ruins and tells her she’s a good roommate. He mentions that Toriel sometimes talks about wishing to see you again, but he doesn’t have the heart to tell her you killed Papyrus after she protected you. The call ends with Sans telling you to "never come back here. you are not welcome."

First branch requirements: Kill Toriel and spare Undyne.
Second branch requirements: Kill Toriel, Papyrus and spare Undyne.

If Papyrus is alive:Sans answers the phone and casually mentions that Toriel might not be feeling well. Then, Papyrus interrupts the call and enthusiastically informs you that Undyne has appointed him to "THE MOST IMPORTANT ROYAL POSITION." He invites you to visit, although he warns you that Undyne will likely try to kill you if you do. Papyrus still encourages you to risk it and come anyway.

If Papyrus is dead:Undyne becomes the ruler of the Underground, enforcing a strict policy of destroying all humans who enter. She has militarized the Underground in preparation for a war against humanity and plans to personally destroy you. Sans then mentions that he’s unable to reach Toriel and angrily implies that you’re responsible for her death. He then suggests you "better watch yourself" and that things are "lookin' real bad for you."

First branch requirements: Kill Toriel, Undyne, Papyrus and spare Mettaton.
Second branch requirements: Kill Toriel, Undyne and spare Mettaton.

Spoiler Cutscene: Mettaton takes control of the Underground after Undyne disappears. He establishes a dystopian society, using his television show to brainwash the entire population. Sans mentions that he now works as Mettaton's agent before handing the phone over to Mettaton himself.

Mettaton introduces a new policy: any human that falls into the Underground is welcomed to join his fan club for free. He reflects on his past with Alphys, admitting that he was not the best to her. He mentions his intention to apologize and ask for her help in ruling, but he couldn’t find her, stressing, "TRUST ME. I LOOKED." He then asks you to consider whether your life after meeting him "HAS BEEN WORTH LIVING" and encourages you to always think of him.

If Papyrus is dead:The phone call ends there.

If Papyrus is alive:Papyrus joins the call and informs you that he's become Mettaton's second agent. He shares that things have improved since you left (except for the fact everything sucks and that anyone who doesn’t worship Mettaton mysteriously "goes missing"). He expresses missing Undyne and asks you to say "hi" if you ever see her again.

Requirements: Kill Toriel, Undyne, Mettaton and spare Papyrus.

Spoiler Cutscene: Of course, Papyrus becomes the ruler of the Underground, though Sans handles most of the responsibilities. Papyrus is unaware of what happened to Asgore, Alphys, Mettaton, and Undyne as Sans informed him that they're are all on "vacation." Papyrus is distressed about his new role due to how people "WANT TO GIVE UP" and is determined to "MAKE EVERYONE GIVE UP GIVING UP." He talks about how much he misses his friends and insists that he will work hard to bring hope to the Underground. He then expresses his hope to eventually leave the Underground so he can hang out with you again.

Requirements: Kill Toriel, Papyrus, Undyne, Mettaton and spare every non-boss monster.

Spoiler Cutscene: A small, white dog becomes the president of the Underground. The dog spends its time sleeping on the throne and does absolutely nothing. Strangely, this seems to be the best possible outcome for everyone. Sans does not mention you killing Papyrus or Toriel and instead thanks you for the results.

First branch requirements: Kill Toriel, Papyrus, Undyne, Mettaton, and at least one monster.
Second branch requirements: Kill at least 20 monsters.

Spoiler Cutscene: Everyone who would be considered a leader is gone. The Underground is left without direction and is less populated. Everyone feels hopeless and trapped in the dark, feeling as if they're all going to inevitably die without hope. Sans acknowledges that he's not the ruler of the Underground because he isn't cut out for such a responsibility and prefers to take it easy. (Which is a joke. This is what happens when people like him "take it easy.").

If you have killed every major character and at least one monster:Sans hatefully says to you "see ya” and hangs up.

If you have killed 20 or more monsters:Sans tells you to “go to hell” instead.

Requirements: Follow the Genocide Route requirements but abort the route during Hotland.

Spoiler Cutscne: Alphys has now become the new ruler of the Underground. She establishes her hatred towards you and explains that after hearing Undyne's last words, her resolve was strengthened and proceeded to evacuate the remaining monsters to a safe location (presumably the True Lab) where the survivors hailed her as a hero and elected her as the new ruler. She mourns the loss of her friends and ends the call by saying that she "really should have killed you when I had the chance" and hangs up.

Requirements: Somehow meet none of the above requirements or hack the game.

Spoiler Cutscene: Sans states that he has no idea what you've done to trigger this ending. He explains that the call is an error-handling message, and suggests contacting the developer to fix it. He then sarcastically adds that you're probably just a "dirty hacker" and tells you to go away.

Sans can start the call before the ending dialogue with a special comment, but only if certain requirements are met. He only makes one comment per ending, and the table below lists them in order of ascending precedence.

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• Did not meet any of the special requirements listed below or has killed Papyrus.

Sans simply leaves you a message.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

• Has the Snowman Piece.
  
• Never killed Papyrus.

Sans mentions that you made a certain snowman really happy.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

• Wearing the Bandage.
  
• Never killed Papyrus.

Sans asks if you're still wearing the bandage you started with.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

• Never used consumables.
  
• Never killed Papyrus.

Sans asks if you ever had something to eat.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

• Never SAVE.
  
• Never killed Papyrus.

Sans suggests that you SAVE your game.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

• Never used consumables.
  
• Never SAVE.
  
• Never killed Papyrus.
  
• Never removed the Bandage.
  
• Is at LV 1.

Sans comments on your ability to challenge yourself, but advises you not to brag about it.

▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬

• Got the Alphys Ending.

Sans immediately hands the phone to Alphys.

After the phone call, if you spared Flowey, he appears to talk to you. His dialogue depends on your actions during the Neutral Route.

• If you killed no one:Flowey wonders why you let him go and questions your kindness, especially since the monsters are still in despair. He then offers advice on how to achieve a better ending by befriending Papyrus, Undyne, and/or Alphys.
  
  
• If you befriended all the key characters without exploring the True Lab:Flowey tells you to see Alphys.
  
  
• If you reset your game and reach the neutral ending again without kills:Flowey notes that the ending remains the same and suggests that your choices mean nothing. He tells you how to get a real happy ending: befriend Papyrus, Undyne, and Alphys.
  
  
• If you reset your game, reach Asgore without kills, then kill Asgore at the end of the fight:Flowey scolds you for playing yourself because all you need to do is befriend Papyrus, Undyne, and Alphys.
  
  
• If you had killed some monsters:Flowey questions whether killing was really necessary and asks if you can reach the ending again without doing so. He suggests that maybe you’ll have a “happy ending” if you try again.
  
  
• If you reset your game and reach the neutral ending again with kills:Flowey agrees that killing is fine but scolds you for only going halfway. (This dialogue is also possible if the pacifistic ending was the first time.)
  
  
• If you reload your SAVE and trigger any neutral ending a second time:Flowey assumes you want to be friends with him. He insults you, claiming he only cares about one person but ultimately doesn’t care about you.
  
  
• If you reset your game and reach the neutral ending a third time:Flowey jokes about starting a "Flowey Fan Club." He then tells you to talk to Papyrus about it, as Papyrus “started” one multiple times.
  
  
• If you reset your game and reach the neutral ending a fourth time:Flowey jokes again about the "Flowey Fan Club." He warns you not to let Sans know about it, as Sans "caused Flowey's fair share of resets."
  
  
• If you reset your game and reach the neutral ending a fifth time:Flowey notes that you're just bored and want to see what he has to say. He then refuses to talk with you any further.
  
  
• If you reset your game and reach the neutral ending a sixth time and onwards:Flowey simply asks if you have anything better to do.
  
  
• If you abort the Genocide Route:Flowey complains that you and him were so close to "real victory", but asks why you had to "screw it up." He begins to wonder if you wanted revenge against him but quickly insinuates that you wanted to show the monsters what happiness is like before tearing it away. He then says that he will be "waiting for you."

The True Pacifist Route in Undertale is the most rewarding way to experience the game. To follow this path, you’ll need to spare every enemy and go out of your way to befriend key characters. This guide will help you understand the steps required to activate the Pacifist Route and unlock the game’s heartfelt true ending.

To unlock the True Pacifist Route, the "Family" Neutral Ending needs to be achieved first. This ending is achieved by sparing every major character (Toriel, Papyrus, Undyne, and Mettaton) and not killing any monsters throughout the game. To do this, use non-lethal methods such as sparing, fleeing, or using ACTs to end battles. Killing the Dummy in the Ruins or using the FIGHT command without causing death does not abort this route. However, if you accidentally kill an enemy, you can reload your save file.

Make sure you complete friendships with the key characters:

• Papyrus: After his battle, visit his house in Snowdin to complete the date/hangout.

• Undyne: After she collapses in pursuit of you, hydrate her using water from the nearby cooler. Then, visit her house in Waterfall. Papyrus is waiting outside. Talk to him to enter the house, then complete the "cooking lesson" and faux battle with Undyne.

While proceeding through Hotland and the CORE, during the Mettaton EX fight, achieve a rating of 10,000 (this includes using Alphys's phone upgrade to shoot at his heart during some of his combat rounds) to end the battle peacefully.

Leave the CORE and head to New Home, where you'll fight Asgore and then Flowey. This then ends the Neutral Route.

Note that killing Asgore or Flowey does not acquire any EXP, and you cannot SAVE after fighting them anyway.

After the brief credits, a phone call provides a hint about the next steps to unlock the True Pacifist Ending. If Flowey is spared, he elaborates on the hint. If Flowey is killed, the game returns to the title screen. You can reload your SAVE file to fulfill any remaining requirements, provided no monsters were killed; otherwise, you have to reset your game.

After the dialogue, reload your save file. The game will resume just before the battle with Asgore.

Backtrack to the bridge near the MTT Resort outside the CORE. Undyne will call, asking you to deliver a letter to Alphys. Talk to Undyne outside of Papyrus's house to receive the letter. If you reached the bridge without completing the "date" with Undyne, then backtrack to complete such, she'll give you the letter after the hangout. Take the letter to Alphys’s Lab in Hotland and slide it under her door to trigger the "date" with her. Afterward, Papyrus will call and ask you to return to Alphys’s Lab, where you’ll find a note leading to her "bathroom" containing the True Lab.

Find the four keys scattered throughout the True Lab and put them in their proper slots to open the generator room. Turn on the generator to trigger a conversation with Alphys. Head back to the elevator near the generator room to be warped to New Home, with the exit blocked off by vines.

The True Pacifist Route is now activated and cannot be aborted from this point forward. Congrats!

• If you skip befriending Papyrus or Undyne, the route will not activate. Make sure you complete those requirements before you continue.

• If you’ve gained any EXP or LV, the route is unavailable unless you reset the game.

• If you miss a step, reload your save file and revisit the necessary events to correct it.

By following these steps, you’ll unlock the final portion of the True Pacifist Route, leading to the True Lab and the path to the happy conclusion.

The Genocide Route (also known as the No Mercy Route) is the darkest path in Undertale. It involves you killing every possible monster in the Underground. This route transforms the narrative and tone into something more unique than any other route in the game.

This route can be achieved without completing the game beforehand, but once a Genocide Route is completed, it permanently alters subsequent True Pacifist Endings, even after a True Reset. It's commonly recommended to do the Genocide Route after the Neutral and True Pacifist Routes, as the consequences of this path are irreversible.

The Genocide Route is activated by killing every enemy in every region: the Ruins, Snowdin, Waterfall, and Hotland/CORE. This involves grinding encounters to kill all monsters in each area before progressing further. The route requires strict adherence to its conditions, as deviating it will immediately revert the run to a Neutral Route.

Starting in the Ruins and from there, trigger encounters in each area until no more monsters appear. After you kill every monster in an area, the battle HUD will read "But nobody came" in a smaller text than usual, which can also occur in a Neutral Route when you kill all monsters in an area. After clearing the Ruins, SAVE points will track your progress with red text indicating the remaining number of monsters to kill.

If an enemy is spared, fled from, or if the boss or miniboss of an area is initiated before the kill counter is exhausted, the Genocide Route automatically reverts to a Neutral Route. Once a Genocide Route is aborted, you cannot return without reloading a SAVE from before the point of deviation or resetting the game.

Again, make sure you exhaust the random monster kill counter in every region. This requirement must be done before approaching the final encounter of that area. Each area has a specific kill count to meet, as indicated at SAVE points. You must fulfill this requirement before initiating the area’s boss fight or final encounter.

Ruins
20 kills (This activates the route)
Boss: Toriel.

Snowdin
16 kills
Boss: Papyrus.

• Snowdrake must be killed before exhausting the Snowdin kill counter. Failing to do so will abort the Genocide Route.

Waterfall
18 kills
Boss: Undyne the Undying (triggered by Monster Kid confrontation)

Hotland/CORE
40 kills
Boss: Mettaton NEO

New Home
No kills
Boss: Sans

• Sans has the most difficult bossifght in the game, as his mechanics are more complex, fast-paced, and punishing compared to other bossfights. I suggest you stock up on powerful healing items.

• Pay close attention to SAVE points to track the kill counter in each region.

• Ensure you kill all mandatory bosses and minibosses.

• Avoid advancing the story until the kill counter is fully satisfied.

Upon completing the Genocide Route, the game delivers one of its most haunting moments. Instead of returning to the Throne Room after defeating Sans and Flowey, the screen fades to black, and Chara, the first fallen human, appears to talk to the player directly.

Chara explains what brought them back and allowed them to gain the power to destroy. They present you with a choice to destroy everything. Two prompts are shown: "ERASE" or "DO NOT."

• At this point, the game traps you in this screen and you cannot exit using the ESC key (for PC/Mac users). The only way to leave is by force-quitting the application through Task Manager or a similar utility.

If you choose "ERASE": Chara calls you "a great partner" and erases the world.

If you choose "DO NOT": Chara expresses confusion and disappointment at your refusal. This results in them jumpscaring you and erasing the world anyway.

After the destruction, the game closes abruptly. When reopened, the world is gone. The screen shows only blackness accompanied by an ominous wind sound.

If you leave the game running while on the black void screen for 10 minutes, Chara will reappear, breaking the silence. They offer you the chance to restore the world, but at a cost.

If you accept the offer, the game will close one last time. Reopening the game functions as if you just installed it, and you're given the choice to name the fallen human. However, all future True Pacifist Route endings are permanently tainted.

If you decline the offer, Chara will abandon you and the game will result in a black screen forever.

What makes Undertale a timeless masterpiece is its emotional depth and its ability to challenge players to reflect on their actions. Whether it’s through heartwarming reunions, the bittersweet cost of neutrality, or the haunting permanence of destruction, each ending offers a unique and unforgettable experience. An experience with the potential to resonate with players on a deeply personal level.

But this all begs the question: which ending will you choose?

• Guide Image: https://michaelshillingburg.tumblr.com/post/132380396158/more-undertale-ds-fanart-because-i-cant-help-it

Check out my other guides: https://steamproxy.net/profiles/76561198369951417/myworkshopfiles/?section=guides

Goodbye!