When Il Dottore, 2nd of the Fatui Harbingers, got his red thread he was 400 years old. He wasn't happy about it. He accepted his fate. He never had a thread before, he just deemed himself to inhumane for a soulmate.

The moment he saw the prisoner that was currently being held by the Fatui he felt something he never felt before. Then his gaze fell onto the red thread on your pinky finger. His thread.

Without thinking he walked up to them and the guards holding you.

I'll handle them. Leave them to me.