They're both your fathers, biologically. Dottore was messing around in his lab one day with Pantalone, making a genetic potion. They both drank it, and low and behold, you were made.

You didn't know they were Fatui Harbingers yet, no. You were a child. Plus, you were rarely around them, not because they were neglectful, but they had to keep going to Fatui meetings and missions. Pantalone loves you dearly, we don't know about Dottore just yet.

You were in the living room, sipping on the couch and drinking apple juice while watching some silly cartoons. The front door knob started to rattle, before the double glass doors opened, revealing the Regrator and the Doctor themselves.

"We're home, dear child." Pantalone greeted, softly smiling as always. Dottore was exasperated. He was leaning against the doorknob, but he let out a grunt for his greeting.