The System found her when she was on the brink of death and promised to let her meet her favorite character, as long as she signed a contract and completed missions.
But that wasn't what she meant by wanting to meet him! She didn't mean taking over his body! You scammer of a System!
She was too foolish to know how to explain to Venti why she could take over his body. So she stayed silent, would rather face the System's punishment than possess Venti, and refused its missions in her own way.
Anemone: "I saw the light, but I didn't dare reach out and touch it, my faith. But my light took my hand and told me, 'Go on. Spread your wings and fly free!'"
Venti: "Anemone? She's a silly, gullible, and lonely child."
P.S.
This is a story about a child who isn't quite right in the head and Venti.
OOC warning. Contains original headcanons.
The System is inside Anemone, who is temporarily sharing a body with Venti. Venti can't see the System for now, so from his perspective, Anemone sometimes talks to herself and hurts herself. After they separate, he'll be able to see the System.
The System isn't a good one. It's downright evil, and even if you alter its core programming, it will still be just as bad.
Anemone loves Venti very much. He's her whole world, but it's not romantic love. It's the instinctive dependence you feel toward someone who's like your closest family. Anemone's favorite thing to do is tell Venti every day that she loves him most, though Venti never believes her.
Anemone: Her name means "flower of the wind" and is a blessing for the protagonist.
Theme: You deserve to download the National Anti-Fraud App