Frisk vs Bete Noire (Battle)

The battle was set after the HSO security measures. It involved Frisk, Bete Noire, Papyrus, Sans, and Asriel.

Context
Frisk, after going outside of their home, decides to search for Bete Noire, and kill her. Asriel, afterward, follows and helps Frisk after they left the house.

Papyrus is seen talking to Gaster, Jessica, and Undyne eventually he is forced to help Frisk since they were about to get killed by a HATE possessed Sans.

Gaster is still wounded but he is getting better after all of the things he has gone through where Toriel is looking for Asriel.

Asgore was wandering in the house until Gaster warned both Toriel and Asgore that he knows where Frisk, Asriel, and Papyrus had gone.

Battle
Frisk chased a pink monster so he could find Betty. Frisk had decided to battle Bete, despite the fact that he wasn't strong enough to fight her.

During the first phase of the battle, Bete easily defeated Frisk without using the power of HATE. Frisk was extremely injured after Betty reminded them of their worst fears and past actions he had done. and losing their DETERMINATION. In the second phase of the battle, Asriel came and tried to save Frisk by fighting Bete. However, she tricked him and Akumu killed Asriel from behind and ate his soul.

In the third phase of the battle, Frisk managed to open his eyes and "Glitch" their stats by drastically increasing their LOVE to 19. For this phase of the battle, Frisk had the upper hand, even if Betty relied on the power of HATE.

Finally, at the last phase of the battle, Bete had the idea to revive Sans by putting HATE inside of his soul. When Sans returned, Papyrus and Gaster felt that something was going wrong with their magic, so Papyrus decided to go look for Sans. Gaster told Papyrus not to go and alerted Asgore and Toriel.

While Frisk was getting beaten by Sans, Papyrus came and saved Frisk, just before Sans could land the final blow. Bete decided to block any path by creating a dome made of HATE to prevent anyone else from interfering.

After that, Papyrus tried to save Sans from Bete without fighting him but by showing "love".

Finally, Sans was saved by Papyrus reminding him that he is his brother. Bete then decided to retreat with the newly achieved soul of Asriel.

Trivia

 * After the events of My Promise, where Chara replaces Frisk, everyone now remembers Chara fighting Betty.