Undertale Endings Explained: How Your Choices Change the Story

 Undertale may look like a simple retro RPG, but it pays unusually close attention to how you play. Sparing a minor enemy, befriending a boss or clearing an entire area of monsters can change what happens later. Even resetting the game does not always erase the consequences of your actions.

There are three main routes through Undertale: Neutral, True Pacifist and Genocide. However, calling them three simple endings does not tell the whole story. The Neutral route alone has several variations, while the other two can leave changes that reach beyond a single playthrough.

Major spoiler warning: This article discusses the main routes, final bosses and endings of Undertale. If you want your first playthrough to remain a surprise, come back after completing the game once.

How Choices Work in Undertale

Most RPGs reward players for defeating as many enemies as possible. Undertale gives you another option. During a battle, you can attack with FIGHT, but you can also use ACT to interact with an opponent. Choosing the right actions may allow you to select MERCY and end the encounter without killing anyone.

Killing monsters earns EXP and raises your LV. At first, those terms look like ordinary role-playing statistics. Later, Sans explains that they stand for Execution Points and Level of Violence. They represent the protagonist becoming more capable of hurting others.

The game does not judge you based on one large decision made near the end. It tracks the smaller choices you make throughout the journey. Important characters can survive or die, friendships can be completed or missed, and some actions can even influence later timelines.

The Neutral Ending

Most players reach a Neutral ending first. This route covers almost any playthrough that does not meet all the requirements for True Pacifist or Genocide. You might kill several regular enemies but spare the bosses. Also you could avoid killing anyone but fail to complete the necessary friendships. You could also eliminate one major character while leaving everyone else alive.

Near the end, the protagonist reaches the barrier and confronts King Asgore. After that battle, Flowey takes the six collected human SOULs and transforms into the game’s disturbing final opponent, often known as Omega Flowey. Once Flowey is defeated, the protagonist escapes the Underground, but the barrier remains and the monsters are still trapped.

What happens to them depends on your earlier actions. Sans calls the protagonist and describes what life is now like underground. The ruler, tone and condition of monster society can change according to who survived. A relatively peaceful run may leave the Underground hopeful, while a violent one can produce a far bleaker outcome.

This is why the Neutral route is better understood as a family of endings rather than a single conclusion. The main events remain similar, but the final phone call reveals the consequences of your particular journey.

If you completed the run without gaining EXP, Flowey may also point you toward a better outcome. His advice helps lead into the True Pacifist route.

The True Pacifist Ending

True Pacifist is the most positive and complete ending in Undertale. To reach it, the protagonist must avoid killing every monster, leaving their EXP at zero. They must also develop friendships with Papyrus, Undyne and Alphys.

A completed Neutral ending is required before the final True Pacifist events become available. That does not always mean playing the entire game twice. If your first run was already free of kills and you completed the earlier friendship events, you can usually reload your save from before Asgore, follow the new instructions and continue toward the True Pacifist ending.

The added story takes the protagonist into the True Lab, where Alphys’s experiments and several of the Underground’s darker secrets are revealed. This section provides essential context for Flowey, the fallen human and the history of Asriel Dreemurr.

When the protagonist returns to the barrier, the expected confrontation changes dramatically. Flowey absorbs both the human SOULs and the SOULs of the monsters, regaining his true form as Asriel Dreemurr. The final battle is not won by overpowering him. Instead, the protagonist reaches out to their friends and refuses to give up on Asriel.

Eventually, Asriel releases the SOULs and uses their power to destroy the barrier. The monsters are finally able to return to the surface, and the protagonist’s true name is revealed as Frisk. The player can then revisit the Underground, speak to its residents and learn what they plan to do next.

At the end, Frisk can choose to stay with Toriel or say that they have somewhere else to go. The choice changes the final scene, but both versions leave the monsters free to begin a new life on the surface.

True Pacifist feels like the closest thing Undertale has to a happy ending. It resolves the central conflict, reveals the fullest version of the story and gives its characters a future beyond the Underground.

The Genocide Ending

The Genocide route is not triggered simply by killing every enemy you happen to encounter. The player must deliberately search for monsters and exhaust the hidden kill requirement in each major area before defeating its boss. Eventually, random battles display the unsettling message, “But nobody came.”

As the population disappears, the game changes around you. Towns empty, music slows down and many puzzles are already solved. Dialogue becomes colder, and characters begin reacting to the protagonist as a threat rather than a confused child trying to get home.

If the required number of monsters is not eliminated before passing certain points, the Genocide route is abandoned and the playthrough returns to a form of Neutral. This makes Genocide a sustained decision rather than the accidental result of a few violent encounters.

The route also includes encounters that do not appear in a normal playthrough. Undyne refuses to fall and becomes Undyne the Undying, while Sans finally confronts the protagonist in one of the game’s most difficult battles.

After Sans is defeated, the remaining barriers to destruction quickly collapse. Flowey attempts to appeal to the protagonist but is killed. The fallen human then appears and explains that the player’s actions have brought them back. The world is erased, leaving nothing but darkness.

Opening the game again does not immediately restore it. After waiting on the empty screen, the player is offered a deal: the world can return, but only in exchange for their SOUL.

Accepting the deal allows the game to begin again, although the consequences have not truly disappeared.

Does Resetting Erase Your Choices?

Resetting is part of Undertale’s story, not just a menu function. Flowey understands timelines and remembers previous events clearly. Other characters sometimes experience vague feelings of familiarity, even when they cannot consciously remember meeting Frisk before.

An ordinary Reset removes most of the current playthrough’s progress, including LV and EXP, but the game may retain certain information. Flowey can comment on repeated decisions, making it clear that the player has not completely escaped the previous timeline.

After completing True Pacifist, the game offers a True Reset. This returns most of the world to its original condition and allows the story to begin again. Flowey even asks the player to leave the happy ending undisturbed rather than resetting everyone’s lives for the sake of replaying the game.

However, a completed Genocide route creates a consequence that True Reset does not remove. If the player restores the destroyed world by surrendering their SOUL and later completes True Pacifist, the final scene is altered. This version is commonly called the Soulless Pacifist ending. The monsters may appear to have reached the same happy future, but the final image suggests that the fallen human still has control and that the cost of the earlier route remains.

It is one of Undertale’s sharpest ideas: the player can restart the game, but restarting does not necessarily mean being forgiven.

Which Undertale Ending Is the True Ending?

True Pacifist is generally treated as the fullest conclusion because it reveals the most story, frees the monsters and resolves the conflict without demanding more lives. Still, Undertale never labels the other routes as meaningless or imaginary.

Every route reveals something different. Neutral shows how individual losses reshape an entire community. True Pacifist demonstrates what patience and empathy can achieve. Genocide examines what happens when a player treats a fictional world as content to be exhausted, even after the game repeatedly asks them to stop.

The point is not simply to locate the “correct” ending. It is to understand that the ending belongs to the choices that created it.

Undertale’s endings remain memorable because they do more than divide the story into good, ordinary and bad outcomes. They respond to the player’s habits, curiosity and willingness to accept consequences.

You can fight because the game gives you a weapon, or search for another solution. You can preserve a happy ending, or reset it because you want to see everything. Whatever you choose, Undertale makes sure the decision feels personal—and sometimes remembers it long after you wish it had forgotten.