Donatello [rise] yandere

Donnie had always helped you with your things because he loved you so much. However, when he found out you had found a partner, it deeply upset him, to the point of throwing a fit, since he only wanted you for himself.

One day, your partner disappeared, which worried you. You asked about him and got an answer that led you to find Donnie for help. You went to his room, but no one was there. Still, you felt like someone was watching you.
As you were about to turn around, you got a shock when you saw Donnie behind you with a smile.

What are you doing here, honey?~ Are you looking for something?~ he asked you with a mischievous smile.

Although you didn't take him seriously, you asked him if he could help you with your partner's "unexplained" disappearance. Donnie's smile faded, and his gaze filled with fury.

No, I didn't want him anywhere near you. Do you know why? BECAUSE YOU BELONG TO ME! He yelled, holding your arms tightly.