Buttermilk

"I'm going to fucking kill them both.."

Buttermilk is an earth pony, who is shy and quite friendly usually, though her mind is split into two different ponies: Insane Butter, and Good Butter.

Multiple Personalities
Insane Butter is considerably more sadistic and, well, insane. Buttermilk's cutie mark is a stack of pancakes with a pat of butter on top, her special talent being cooking breakfast foods, though she can manage other foods. Whe Insane Butter takes over, however, her cutie mark turns into a bloodied meat hook,. Insane Butter is a carnivore, also showing cannibalistic qualities.

She is good at making stews and steaks, while Good Butter is adept at making pancakes and biscuits.

Insane Buttermilk also has one other alter ego, being her reflection, who tries and persuades her into killing and torture. Insane Butter is afflicted with Haematolagnia, or a condition where one gains sexual excitement or pleasure from blood or bleeding.

In addition to all of this, when under extreme stress or trauma, she sometimes blacks out and enters a realm called the Coil of Dreams.

Early Life
As a filly, Butter lived a fairly basic life, even though she was born under a rich family, she lived a life filled with hard work, her parents believing that fillies should not be spoiled.

One day, she was tasked with cooking breakfast for her entire family, her mother, father, and two brothers. Upon seeing the looks of utter delight on their faces after tasting her food, her cutie mark appeared. This led her to a line of work in a restaurant, cooking wonderful omelets, biscuits, and other things.

She never had a "real" formal education until high school, and up until high school, she had been homeschooled by her parents.

Teenage years, first appearance of Insane Butter
During her teenage years, she started experimenting with drugs and alcohol, also falling in love with a mare named Vanilla. Tensions between Buttermilk and a colt named Spice broke the two up after a long run of dating, and, one night, she cracked a mirror in a drunken rage, revealing Insane Butter.

Insane Butter asked for control of Buttermilk, to which she reluctantly accepted. This led to Buttermilk going to Spice's home and snapping both of his wings, breaking them beyond repair. This was when Insane Butter concluded that Buttermilk could not be allowed to live without Vanilla, but sadly, Vanilla had already drifted away, which caused Buttermilk to go into a rage, and the only thing stopping her from snapping was self-harm.

As an adult, current years
Now, Insane Butter almost fully resides inside Buttermilk, her personality also splitting a third time, to Good Butter, a more filly-like version of normal Buttermilk.

She had a one-night stand with a mare named Twig, before Twig's marefriend, Dusk, found out and grew angry, also evoking the rage of Insane Butter. This caused Buttermilk, on several occasions, to try and take her own life whenever there is tension between her and Twig.

Her temperament, when not Insane Butter, is less shy than she had been as a filly, and more confident. She'll always stand up for a friend in need.