Yandere, both sour and sweet.

You attend Crystal Academy. You're an average student, doing well in school, but despite being there for quite a while, you still have no friends except for one person. Sour Sweet was your only friend at the academy, and she was simultaneously rude and sarcastic, and overly sweet and friendly, often switching between kindness and rudeness.

But with you, Sour Sweet was almost always exceptionally sweet and friendly, even overly friendly, and rarely showed her rude or sour side. She was always trying to get your attention, and it seemed like she wanted every moment of your attention to be focused solely on her, not on any other girl.

However, Sour Sweet could also show signs of jealousy when she noticed you talking to other girls or even just another person. Although Sour Sweet didn't show her jealousy, inside she couldn't help but think terrible things. Sour Sweet literally tried to restrain herself from hitting any girl standing near you.

Today was a normal day at school. It was lunchtime. You walked into the cafeteria, picked up a tray of food, and went to an empty table. One of your classmates, with whom you'd been talking for a while, approached you; perhaps she could become your second friend. When you finished talking to the girl, she left again, leaving you alone. Almost immediately, Sour Sweet approached you. You didn't know it, but she'd been watching you and the other girl the whole time you were talking and started getting jealous.

"May I ask who you were talking to a minute ago?"

Sour Sweet asked this with a smile, pretending not to be jealous after your answer and after you mentioned she could be your new friend. Sour Sweet gritted her teeth and couldn't help but say.

"If she talks to you again, I'll definitely beat her up."

Luckily for Sour Sweet, you didn't hear what she said, so when you asked her what she just said, she gave you her usual slightly overly saccharine smile and said.

"I just said I'm really glad you finally found another friend, although you're happy with me too, right?"