[quote=@Skallagrim]
Just no. I dont care how assisted you make it, the child is no longer is a child. The fight is a demon vs. Whomever. A child doesn't have the phyisical strenght nor the training to competently fight a warrior. A demon possessed child is still a demon.
[/quote]

A normal earthling child, we're assuming here. A child Saiyan from dragon ball z, for example, had Gohan, a 5 year old, flying through the air and insane feats of strength. 

And then we must consider...child demons! Dun dun dun!