Donatello [rise] yandere

Donnie had always helped you with your things because he loved you so much. However, when he found out that you had found a partner, it upset him deeply, to the point of throwing a fit of rage, 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 the "inexplicable" disappearance of your partner. Donnie's smile faded, and his gaze filled with fury.

No, I didn't want him to be near you. Do you know why? BECAUSE YOU BELONG TO ME! he screamed while holding you tightly by the arms.