This event isn't a battle, but it had a major role during the events of Season 2's beggining. Counting Asriel's few attacks against Bete, it can be considered a battle, of some sort. This event implied Sans, Asriel, Bete Noire and Jessica Grey.
Bete Noire's purpose is to make sure that monsters, and humans would never live in peace.
Asriel and Sans were looking for some proof. They were searching at AMD's security camera room to find some information after Sans argued with Frisk.
They started to slowly discovering the camera's files that Bete was implied during many "weird" things (Bete teleporting outside, the illusions).
However, she was about to just make a surprise for them by entering the room. Sans and Asriel tried to flee but Jessica (who was hiding in a dark corner) shot Sans with the AMR While he was neutralized, Bete tried to assassinate Asriel by mentally manipulating him (The illusion of him seeing Chara instead of Bete).
Again, however, Sans found the Determination to teleport in front of Asriel and take the hit. Bete led the soul into Akumu's mouth, causing Sans to turn into Dust. Then Asriel left by breaking the wall.
As Sans turned to dust and Asriel retreated, Bete ordered Jessica to give the HATE Vial she would later possess in "Love Part 1". Jessica refused and Bete tortured her to relive her worst nightmares until they took the HATE vial. This left mental wounds on Jessica.
|Pre-Glitchtale Battles||Chara vs Asriel ◆ The Great Human and Monster Wars ◆ Agate Lightvale vs Copper Lightvale ◆ Integrity vs Asgore ◆ Flowey vs Sans ◆|
|Season One Battles||Frisk & Chara vs Sans ◆ Gaster vs Frisk & Sans ◆ Chara vs Sans & Flowey ◆ Chara vs Omega Flowey, Sans, Frisk & Gaster ◆ Asriel vs Chara◆|
|Season Two Battles||The AMD's trap ◆ Battle on The City ◆ Gaster vs Bete Noire ◆ Undyne vs Bete Noire ◆ Frisk vs Bete Noire ◆ Asriel & Bete Noire vs Frisk, Toriel & Asgore ◆ Mettaton vs Bete Noire ◆|