Undertale Last Breath
One thing we see in Undertale Last Breath is how things change when Frisk takes the genocidal route for the 30th time. Generating a very angry Sans behavior that suffers several things during the course of this sad story for the monsters of Undertale. So now I'll tell you a little bit about what's going on with Sans and how it all works.
How does Sans realize what is happening at Undertale Last Breath?
What this story tells us is that Sans finally realizes all the massacres that Frisk the human had committed against his friends. For if you make 30 games with the genocidal route comes W.D Gaster, the former real scientist, about his intentions and revived his memories of previous restarts.
We just need to put ourselves in Sans' shoes and know that everyone he knew and appreciated, including his brother Papyrus. This part is very important to review because you can appreciate how Sans had Papyrus' scarf in a corner, making reference that you have a great grudge against Frisk.
Knowing that the Human being will never stop killing all his friends, he will not have any other option to fight to defend them. Since only he knows everything that's going on and has to try. He has no choice but to risk his own life to stop Frisk from going crazy.
Before he fights, Sans promises to make Frisk pay for everything he has done, even if it is with his last breath.
Moments earlier ...
Sans was resting as usual, but he suddenly woke up because of a spiritual entity. It was W. D Gaster tells him all this, but he refuses to believe it. Knowing that it would not convince him of the seriousness of the matter, he decides to show him all the memories of your lives behind you, being in 30 games today.
This is when Sans believes completely and is a little horrified by such evil. So he goes to his father to teach him some moves to confront Frisk knowing that he will keep treating the monsters with his toys.
When Sans finally meets Frisk after finishing off all his friends, Sans makes a move, lying to him that there was another, much better way. But suddenly Sans gets hit by Frisk with his sword.
Sans attacks by summoning bones to protect himself while he recovers his health which left him badly hurt. Already a cut is visible in Sans' chest. As Frisk manages to wear him down, Sans falls back to the ground.
Leaving Sans with a .0001 waiting for the last punch from Frisk to end his life once and for all. He realizes when Frisk hits him that something is protecting him.
Something is protecting him and trying to help him
That's when we notice how something takes control of Sans' body, as we see a crack forming in his skull that reaches his left eye. That's when Sans starts attacking like a crazy maniac.
But unfortunately Sans runs out of magic and Frisk manages to hit him once more. He manages to leave Sans with very little life. He was about to stop smiling, but he vanished into a trail of dust that meant he couldn't beat him this time. That he died, but not sad about the defeat and that he left, but always in his characteristic style, smiling. And that's what we can have in Undertale Last Breath.