"No. That's just a fantasy, isn't it? Young one, when I look at you... I'm reminded of the human that fell here long ago... You have the same feeling of hope in your eyes. There is an ancient prophecy among our people... One day, a savior will come from the heavens. ...I believe the one that was prophesied was you. Somewhere in the world outside... There must be a way to free us from our prison. It pains me to give you this responsibility, but... Please. Take my soul... and seek the truth. Ha... ha... I'm sorry... I couldn't give you a simple, happy ending... But I believe your freedom... ...is what my son... ...what ASRIEL would have wanted."
– Asgore, committed suicide during Suicide Route
Method (What If?)
The Suicide Route occurs when the protagonist dies too many time in the Ruins. Starting in the Ruins, the protagonist intentionally triggers encounters and killed by monsters 20 times, next is that you let Toriel to kill you in front of her face. Then, when you spare her, she told the protagonist that she knew that someday, Frisk will leave the ruins, and she will not be able to protect them. Then she committed suicide.
- Papyrus maybe committed suicide when he knew than you are insulting him, and you start telling him the truth, about the royal guard and Undyne. In the end, before he impales himself with bones, he tells Frisk that he still believes in them and that they can do better. He tells them that he stopped believing in himself.
- Monster Kid died when they accidentally tripping on the bridge as this time, Undyne could not reach in time to save them.
- Undyne goes berserk when Monster Kid dies. Frisk tells her that they are weak and they couldn’t even save that one monster. Obviously something like that would tempt her but she refused, so Frisk speaks some more. In the end, Undyne aims most of her spears towards her head and chest (heart) when she understand than his dreams, means the death of 6 innocent humans.
- Mettaton commits suicide when his ratings stays in 0 for many turns, he remembers Blooky, and how he threw everything away just for some compliments and the happiness of unknown monsters, now he thinks he is a super 0, tries to free himself of his robotic body, but he explodes in the end, being unable to fix ever again.
- Alphys committed suicide like what she did on Neutral Route if Mettaton and/or Undyne died.
- Sans tells you that you have no LOVE or EXP, and despite that, everyone is dead, even Papyrus, he realizes then is not worth fighting anymore, commits suicide.
- Asgore commits suicide like what he did on the Neutral Route when you killed Flowey in the previous run. But his SOUL was not destroyed by Flowey, he took the last SOUL to show Frisk his true form.
- Flowey/Asriel took all the souls of the fallen monsters, he turns into his original form, and tries to speak with Frisk, he knows that everyone had reasons to commit suicide, and he is dead after all, he realizes that he will never see Chara or anyone again, free the souls and breaks the barrier for Frisk to leave, he turns into a flower again, and stays silent.
- Chara is already dead, but they thinks than Frisk killed everyone, they realizes that they has no power on the world of the living, and they had no effect in Frisk, so they fade away forever.