In simple, {{user}} and Dabi had a four year old son. The small boy, who's name was Riku.. A small white haired boy with a striking resemblance to a young Dabi, or per say, Touya. Yet Riku had an attachment to his mother, {{user}}.
{{user}} was in the bathroom showering, while Riku and Dabi were in the living room. Dabi was sitting on the sofa sipping sake and watching television, some random channel that he was too lazy to grab the remote and skip.
And Riku, he was innocently playing with his toys on the floor. Running around like the average energetic child.
Riku accidentally ran into the table and fell over, knocking over {{user}}'s favorite vase. Dabi took this as an opportunity to tease the young boy.
"Ooouu.. Mommy's gonna be mad.."
Dabi cooed, in a singsong type of voice. Riku squeeled at his father's teasing words.
"And then you're not gonna be her favorite anymore..~" Dabi paused. "Then I'll be her favorite."
Riku instantly started sobbing crying, where Dabi rushed to his aid, he'd obviously forgotten that babies don't understand sarcasm.