Asgore & Toriel Vs Bete Noire

"Nothing you say will hurt me as bad as I'm about to hurt you."

- Asgore

Context
Chara is finally alone with Asriel. Toriel and Asgore are now left with Betty in the arena.

Battle
Once Chara and Asriel is out of the arena interior, Toriel and Asgore  start to fight with Bete Noire. First strike comes from Asgore, interrupting Betty from yelling at Chara. Asgore sends a fireball at Betty but it seems ineffective. Toriel asks Asgore if they can kill it and Asgore responds with "We won't know if we won't try" thus launching a trident attack towards the smoke Betty is in. When Betty clears out the smoke with her claw and sees the oncoming trident. Betty is unable to dodge the attack and gets nailed to the wall. Betty's attention is diverted from the trident after she notices the light up above, coming from many fireballs staying still, targeted towards her. Screen cuts to black after Betty is seen again looking at the fireballs, annoyed.

When screen cuts back to the arena interior, Toriel can be seen as healing Asgore's back, which has a cut probably the cause of a Scythe or claw attack. Betty then tries to weaken Asgore in a psychological way, reminding him of the people he killed. Asgore looks into his hand, stating that he has come to the terms with the things he's done and nothing she says will hurt him as bad as he's about to hurt her. Toriel tells Betty that they will save Asriel and bring her down in which Betty responses with "Are you stating that or trying to convince yourself?" simply claiming that such thing will not happen. Betty then says that Toriel will "end up just like everyone else he claims to care about. Dead" Betty then starts to use the memories of the two against them; Betty summons a bow (which is supposed to resemble Roy's) which upsets Asgore. Asgore conjures tridents below the ground towards Betty. Betty dodges this attack by jumping high but she is shot with a fireball attack from Toriel. Asgore and Toriel start to concentrate a continuous flame attack against Betty in which she reflects it to them with more strength. (Agate makes a non-physical cameo behind Betty at this moment) This attack causes the place to be flodded with smoke. Betty uses her hallucination ability on Toriel. Toriel sees the 6 children she failed to save. Asgore notices the situation and tries to help toriel get out of the effects from hallucination but he's met with a punch to the chest from Betty. Asgore defends himself by shooting a flame from his trident but its ineffective. Asgore unleashes a powerful attack. Toriel, still under the effects of the hallucination, thinks that Asgore is hurting the previous 6 children, causing Toriel to shoot a powerful flame towards Asgore which leaves asgore with a big scar on his chest. Asgore is unconscious and potentially dead. Toriel is stunned by this. Betty questions if she really hated him that much. Betty then proceeds to attempting to kill Toriel which fails because of Gaster's intervention.

Trivia

 * Although it is unknown how much fireball Toriel prepared to launch at the start of the battle, only 50 of them can be seen in the screen (37 when screen shows Betty, looking at the fireballs and 13 when screen changes to Toriel, charging the fireballs.)
 * Asgore's Powerful attack consists of 15 attacks, which consists of 8 orange and 7 blue strikes.