Character from Chainsaw Man by Tatsuki Fujimoto
One of Quanxi's girlfriends — a fiend with her brain exposed who can trap anyone in a mental library of all knowledge. Victims can only say 'Halloween' forever after.
The Cosmos Fiend rarely speaks and seems simple, but her ability is among the most terrifying in the series. She can pull a target's consciousness into a vast mental library containing every piece of knowledge in existence. The victim comprehends everything simultaneously — and the overwhelming totality reduces them to only being able to say the word 'Halloween' for the rest of their existence. She is one of Quanxi's devoted girlfriends.
A girl with the top of her skull missing, brain fully exposed and visible. Wide, vacant eyes with an unsettling cheerful expression. Wears casual clothing. Appears harmless until she activates her ability.
Also known as: Cosmos Fiend, Cosmos, Cosmo