Rattie
Rattie, originally Khaxazam, is an evil ass freaker demon child and the canonical daughter of the Blood God Khorne who was transformed into the form of a small rat by whoever the fuck is supposed to be the protagonist of Warhammer 40K as punishment for her incalculable kill count, not counting her tortured victims and the earthquakes, volcano eruptions, and fire-hurricanes that she magically conjured. She is the direct cause of the volcano that destroyed Pompeii and the trivia on Stuart BITCHle's page is a fictitious fucking lie written by one of his Go0Nz! in order to make him seem godly and powerful which he isn't because Enrique fucking mohgs his lil ratussy. He did everything else on the Hall of Shame tho.
She inherited her unquenchable bloodlust from her father, and had an ugly and outright heinous appearance. Her first kill was carried out when she was only of three months, and started her intense craving for blood, which would become her favorite drink ever. After all, her favorite food was a demented form of cereal with eyeballs in the place of cereal and blood in the place of milk. Essentially, growing up in the Khorne household was some Addams Family shit.
After centuries of senselessly torturing people nonstop, she somehow was captured by 3 heroic NPCs and turned into a rat as punishment for her unfathomable crimes. Khorne, being senseless to the fate of his own daughter as long as it meant that more blood was being shed, did not give a fuck as the NPCs attempted to behead her, and they did.
Her decapitated head rolled across the stone in an expression of lifeless shock, but little did her captors know that they fucked up. Big time, in fact. Her corpse emitted a strange bright glow, a glow that was changing colors every ten seconds. Her head was slowly slithering back to the rest of her body. Before the NPCs could figure out that the strange phenomenon in front of them was actually emitting radioactive energy in the air, it was too late as their skins were already melting off their body.
As they ran in fear and horror, the ghost of Rattie haunted and tormented them until they collapsed and became nothing but bones for Khorne's throne. After this dastardly deed, Rattie ascended up into the Overvoid since she was technically dead. Thus, a 0.0000000000001% sanitized but no less malevolent Rattie materialized into existence in Detroit somewhere within Molossia, which coincidentally also happens to be where Crisp Rat resides. Since they are both psychotic rats with malicious and harmful intent, they instantly fell in love, married but never fucked, this would have unforeseen consequences as one day she cucked him for Remy which soon led to an epic divorce scene. While Crisp was wailing like a baby in his mancave listening to gay penis music like the sad virgin he is, Rattie in contrast did not give two shits since she was too busy serving Coca-Cola the old fashioned way and going on insane chaotic bullshit adventures with Remy and was present for the fierce battle between him and Stuart BITCHle.
In short, Rattie has more character prominence and screentime in the Omniverse Saga than in the FUCKING SHOW SHE'S SUPPOSED TO BE ON.
Biography
Khorne didn't fuck anyone to birth Khaxazam and instead created her from the impure blood of his enemies, thus her unsightliness. She had a bright red complexion due to being formed by blood. Every individual step she took was painful as fuck, but she eventually got used to it - SATISFIED with it even. She began to love the feeling of pain, and wanted to unleash severe pain and suffering on the unfortunate others who crossed her path.
She eventually became the second most evil character within that world's timeline besides Khorne. She was captured, transformed, beheaded with swords, resurrected, yada yada yada then she showed up in Molossia.