In "Kid Stuff" is the third episode of the first season of Justice League Unlimited, Morgaine Le Fay leads her son Mordred to an immensely powerful artifact: the Amulet of First Magic. The, Mordre only casts a spell to banish all adults from the world. Morgaine appears for Justice League, raging against her son's treachery and offer to help the Justice League members to defeat him and reverse the spell. She is not powerful enough to overcome the spell, but she can exploit a loophole in it: born "The Junior Justice League".
Diana showed herself willingly in the new condition, mostly because she was taller than all the boys. Just as she is as an adult, the Amazon girl shows a lot of initiative and willingness to fight challenges. However, she also acts with a commanding voice and, when necessary, acts kindly. Her crush on Bruce also comes out much more prominently in this new condition: she tries to play tsundere-girl, but fails because of the dense personality of Bat Boy.