How to Unlock the True Pacifist Ending in Undertale

This guide will show you how to unlock the True Pacifist Ending guide for UNDERTALE.


This ending can be considered to be the “true ending” to Undertale, leading to a happy conclusion and the complete credits.

Upon completing the Neutral Route, you will receive a phone call after the credits that provides a hint to the next requirement for getting the True Pacifist Ending. If Flowey is spared, he appears afterward and elaborates on the hint, but if he is killed, the game immediately returns to the title screen. You can then reload your SAVE file to fulfill any missing requirements as long as you haven’t gained any EXP/LOVE; otherwise, you have to reset your game.

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

The list of requirements are as follows:

Throughout the game, never kill any enemies or gain any EXP/LV; essentially, only use non-lethal battle exits (spare, flee, or battle-ending ACTs). FIGHTing monsters or killing the Dummy in the Ruins does not cause this route to be aborted, as they do not accrue EXP. However, if you accidentally kill a monster, you can simply reload your save file.

  • After fighting Papyrus, visit his house and complete the date/hangout with him.
  • After Undyne passes out from pursuing you, get a cup of water from the nearby water cooler and pour it on her.

After hydrating her, go to Waterfall and go to Undyne’s house. Papyrus is waiting outside. Talk to him to enter the house, then complete the “cooking lesson” and faux battle with Undyne.

Go through Hotland and the CORE. In Mettaton EX’s fight, get the ratings to 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.

The Flawed Pacifist ending needs to be achieved first. The next series of events can be triggered in two ways, provided that no EXP/LV have been gained: either by going through the game normally from the beginning after completing a Neutral Route, or by reloading the final save file of a Neutral Route.

Backtrack out of the CORE towards the MTT Resort, to the bridge connecting the two places. There, Undyne will call you, asking to deliver a letter for her. Talk to Undyne outside of Papyrus’s house to receive Undyne’s 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.

Put the letter under the door of Alphys’s Lab and complete the “date” with her.

Upon leaving the Garbage Dump (where befriending Alphys ends), Papyrus calls and tells you to meet Alphys at her lab. Return to Alphys’s Lab to find a note leading to her “bathroom” containing the True Lab. (Upon entering the True Lab, the True Pacifist Route cannot be aborted.)

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. This signals that the True Pacifist Ending will occur. It is impossible to leave New Home after this point.

Completing Friendships

If Papyrus has not been befriended, backtrack to his house in Snowdin, where he is standing outside. Interact with him to initiate the date/hangout.

If Undyne has not been befriended, backtrack to her house in Waterfall, where Papyrus is standing outside. Interact with Papyrus to initiate the Hangout.

Befriending Alphys

At the entrance to the CORE, Undyne calls you (at the behest of Papyrus) to ask you to deliver her letter to Alphys. (If Undyne was befriended in the Neutral-Pacifist Route, she will give you the letter immediately after befriending her.)


Frisk can go through the Underground and talk to NPCs, including the several monsters encountered only during battle encounters. They express their feelings, often about being free at last. In the beginning area with the golden flowers, Asriel can be found tending the flowers and can be talked to.

True Reset

After reopening the game after the True Pacifist ending, The game’s menu has none of Frisk’s friends, as they have all left. You can load your SAVE, which takes place before the ending, and you can replay the credits from there. The menu’s reset option is replaced with ‘True Reset’; this allows you to rename the Fallen Human. Choosing a name resets the game and removes everybody’s (including Frisk’s and Flowey’s) memories.

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