The Last Corridor is a yellow-hued room adorned with windows bearing the Delta Rune. White light shines through the mosaic windows, and Greek pillars border the corridor in both the foreground and background.
The goldenrod palette of this room may allude to the yellow SOUL which represents justice. The dual meaning of the word "justice" is a pun; Sans acts as a justice or a judge, and he also is just in character because he displays neutrality and objectivity. Sans also delivers justice to the protagonist if they are on the Genocide Route.
After walking halfway through the corridor, the protagonist encounters Sans as a silhouetted figure, paralleling their first encounter with him in Snowdin Forest. He initially speaks without his typeface and explains EXP and LOVE. Sans then asks the protagonist to look within themself and question if they have done the right thing. After a moment, he comments that it does not matter what the protagonist said, so long as they were honest with themself. Loading a SAVE and hearing Sans's introduction again prompts him to judge the protagonist on their earned EXP.
If the protagonist gained no EXP in a Neutral Route, Sans abridges his introductory dialogue and comments on their lack of LOVE. After this judgment, reloading a SAVE and talking to Sans prompts him to offer a secret codeword. After repeating this process a few times, the protagonist obtains a key to Sans's room.
After his dialogue, Sans vanishes, and the protagonist can progress.
True Pacifist Route
Sans is not present in the Last Corridor during a True Pacifist Route. Two instances lead to his absence:
- Completing any Neutral Route, restarting from the beginning, and completing a True Pacifist Route
- Completing a Neutral Route with no EXP earned, sparing Flowey after his battle, backtracking to befriend Papyrus, Undyne, and Alphys, and exploring the True Lab
In addition to the SAVE Point, a box is present, unlike in other routes. This is the location of the final encounter against Sans, in the Genocide Route. Sans attempts to prevent the protagonist from progressing because he believes they are the entity that ends the timeline.
After defeating Sans, the protagonist can progress to the Throne Room.
- ↑ "You will be judged for your every action. You will be judged for every EXP you've earned." - Sans
- ↑ "Look inside yourself. Have you really done the right thing? And, considering what you've done... What will you do now?" - Sans
- ↑ "you never gained LOVE, but you gained love. does that make sense? maybe not." - Sans
- ↑ "i kind of have a secret codeword that only i know. so i know if someone tells it to me... they'll have to be a time traveller." - Sans
- ↑ "our reports showed a massive anomaly in the timespace continuum. timelines jumping left and right, stopping and starting... until suddenly, everything ends. heh heh heh... that's your fault, isn't it?" - Sans