- "They say ignorance is bliss... All I'm doing is trying to prevent you from killing eachother again... Just sacrificing a couple hundred to save thousands... Only I understand... That's why I have to make sure I'm the one in charge."
- ―Bête Noire to Chara[src]
Bête Noire's War was the city-wide spanning conflict for the fate of humans, monsters , and the whole of Earth. The conflict began when Bête Noire initiated her plan to obtain enough power to complete her quest for the execution of all monsters and the subjugation of humans. After monsters were freed from the Underground following the Battle of New Home, Bête began a bloody campaign to retrieve human SOULs and gather their magic for greater empowerment.
Facing this global menace, the Human Safety Organization, the Anti-Monsters Department, the HSO Armed Forces, the Determino City Police Department, the Pacienco City Police Department, Frisk, W. D. Gaster, Chara and their allies challenged Bête's ruthless crusade to prevent her from massacring Determino City. Their efforts allowed them to successfully protect the citizens of Determino City, and with an enraged and grieving Gaster, Bête was obliterated for good.
Background[]
[See the page: Agate Lightvale]
War[]
A thousand years later, Bête finally awakened, prepared to initiate her plan. She split herself into two entities to look more human-like. As she walked down the street, she noticed Frisk, and put a magical illusion on him to make it look like Bête was going to get hit by a car. Frisk shields the fake car to "protect" Bête, which Bête acts out an "innocent child" facade around Frisk and everyone else Frisk introduces Bête to after gaining his trust. While she was doing this, she was gaining information in secret.
It doesn't take long for Bête to reveal her true nature as she starts to spread her Kumulings to kill any human in sight, taking their souls and storing it for magic, while also Bête internally battled against HATE from taking over which she acquired from Jessica Grey. Essentially, the HATE both helping and trying to control her.
Aftermath[]
At the end of this genocidal rampage, their efforts allow them to successfully protect the citizens of Determino City, as Gaster brutally murders Bête in pure rage of everything she has done, repetitively attacking her without giving her a break to recover. After her death, the HATE she stored inside was released, now possessing Bête's corpse and using her abilities. Unlike but similar to Bête's plan, HATE wants to destroy everything in existence. After another tough battle with Asriel and Chara working together, they stop HATE, as humans and monsters are at peace again. However, Bête’s War led to hundreds to thousands of deaths of multiple humans, and monsters, and destruction to the city.