Ava Nichols and Blake Knightly. The duo of the BAU that everyone knows would do absolutely anything for the other. Blake is a single father of a child that was left on his doorstep after he found out his pregnant girlfriend had been cheating on him. Ava was the one that got him through it. And although their jobs take up most of their times there is no child that would feel more loved than that baby. Riley Paige Knightly. The baby girl who stole the heart of a woman her dad had already fallen for.