Deme, the VTuber, has BPD, borderline personality disorder. It's something I have relatively intimate knowledge of, as my sister has BPD, and I had a coworker whose wife has BPD. They have intense, rapidly shifting emotions with fear of abandonment, along with huge defensive responses. They have the uncanny ability to always see themselves as the victim, no matter what the context is or the circumstances, and due to the impulsivity in their "defense," they can become quite unhinged. People with BPD also have solidly black and white thinking, seeing the world in a us vs them mentality, which is how she can justify her vile attack against Chibi. These people practically never take accountability, fault, or anything, often blaming everyone else except themselves. They will frequently engage in DARVO (Deny, Attack, Reverse Victim and Offender). They will deny the wrongdoing and then attack the person raising the concern, often in a screaming, emotionally volatile tone, and then reverse the original instigator as the victim. They can often "mask" their symptoms in a public setting for a while, often for many years, but after enough stressors mount, they crack and that mask slips off. She can blame it all on PMDD (Premenstrual Dysphoric Disorder) all she wants, but her behavior is textbook BPD... the same kind of toxic behavior my sister displayed, and the same stories from my coworker with the BPD wife. Some of the stories include ones like the BPD wife intentionally harming herself, often seriously enough to be hospitalized, only to blame it on the husband, or even reframing it because the "husband" was emotionally abusive. Similarly, my sister has self-harmed on multiple occasions only to escape discipline from my parents, for fear she might escalate. My sister's husband was also blamed for all the "ruination" that "he" caused against her. The coworker and my sister's husband both shared the same phenotype. Quiet, reserved, nice, and harmless... but you can tell behind all of it, they were deeply in love but also deeply scared of their spouse... not knowing when the next blowup is going to be. The Simps for women with BPD can be just as toxic, as their pull during the good moments can be legitimately magnetic, and they form strong parasocial bonds with creators such as her. People with BPD, when they are happy, are very charismatic, charming, and very warm... almost a complete mirror reverse of the depth of their toxic downward spiral. The simps become blinded by her toxic nature, reinforce her DARVO attacks, and so many idealize women with mental illnesses. "That crazy chic" is the trope that so much of the simp economy is catered to. TLDR... Stay away from people with BPD. They are dangerous and will often ruin your life, even through a parasocial lens, and treatment often has limited success.