I decided to do this quick one-shot, as we never actually see Nanako's shadow in the game. It's set just after the Kunino-Sagiri fight, where Nanako is discovered to be very ill thanks to prolonged exposure to the TV world.
Persona 4 is owned by Atlus. This work is a parody, and thus falls under transformative fair use for copyright purposes.
Yu, Yosuke, Yukiko, and Naoto had just defeated Kunino-Sagiri when they were running to save Nanako. Everyone was in a panic as Yu sprinted down the stairs. He was rushing from paradise to paradise, in a mad dash for the exit. However, along the way they encountered an obstacle on the way...
It was a small child. She was similar in every way to Nanako, except with a thin purple haze around her abdomen. She opened her small mouth to speak. "Excuse me. Where do you think you're carrying me?"
Yu was having none of this. "Out of here, where she's safe!"
"And where you can't heal her. Ugh, fine. Since I always have to do everything myself, again: I'll do it for you." The child then cast diarahan on Nanako. She instantly regained consciousness, and was back to her happy self.
"Phew, I feel better now! What was that?"
"Just some healing because no-one else was bright enough to do it for me. Ever since that incident, I've been having to do everything myself, others unable to assist me."
"Oh, I know the feeling. Well, it means that when you grow up, you'll be a more mature and successful person!"
Nanako's innocent smile was infectious, and the girl became happy. "Ah, at least I can rely on myself to talk me into sense."
"Huh? You're me? Big bro, you never told me about having an alternate version of myself! Well, since we are each-other, I'm sure we can be best friends as we'd always know when the other is free." Nanako rushed her shadow, and grabbed her by the wrist, before attempting to drag her to Yu and company. "Come on, it'll be fun! Besides, if I've got another me, we both have someone to rely on!"
At this point, a blue light surrounded Nanako's shadow. She changed into an angelic figure standing on a small floating island, not more than a metre in diameter. This persona stood alone on the island, with minimal frills, but was had several bridges coming off the island, ready to deliver help when necessary. At this point, Nanako looked around, confused. "What happened?"
Yu chuckled. "You managed to get your persona. And we didn't need to fight to get it." The comment had a hint of salt directed at the other party members. They groaned at the fact that Nanako was, once again, more mature than they could ever hope to be.
"Huh? You normally have to fight to gain personas? Well, it's a good job I didn't have to put you through that. After all, I wouldn't be able to handle myself if I were fighting something..."
Yosuke decided to cheer Nanako up. "We weren't able to handle ourselves either. We just needed Yu-kun to deus-ex-machina his way to saving us. But you managed to sort out your shadow all on your own. I must admit, I'm a tad jealous..."
"So, I was the only one who could sort myself out? Wow. My shadow was right; I don't need others. But, I do still want to be with others, as it's fun!" Nanako then ran back to the party, and grabbed Yu and Yosuke. "Come on, we were going this way, right?"
She ran to the exit at a pace not even Chie could match. Naoto was lagging behind the most. (This is why we use cars for police chases...) she cursed as she tried desperately to keep up.
Nanako then jumped from island to island, making a shortcut to the exit. Whenever she missed a jump, her persona carried her to the next area. After she reached the exit, she looked back to see the rest of the gang... Who were about 3 floors behind. "Come on! Last one down's a rotten egg!"
Chie became excited. "It's a race, huh? Bring it on!"
Yukiko threw Namatame to her persona, so she could run faster through the teleporters. Yu ran as fast as he could, but didn't do much else. Kanji was also the type to be swift. He made a few shortcuts for himself by punching down the decrepit walls. Chie was quite fast anyway, but decided to make some shortcuts for herself with the occasional jump. Naoto realized her persona could fly, and took the shortest path through the air. Rise also called on her persona. Since shadow Rise ws very used to traversing poles, and could analyse anything, she easily swung across the edges and undersides of the floating islands. Yoskue was specialized in wind, so he was very quick as soon as he broke out his persona. He could also use Garudyne to fly over some small gaps. As for Teddie, his large costume allowed him to survive falls. He hopped on a missile from his persona, jumped off, summoned his persona, used another missile, ans quickly made it to the next islands, bouncing off the ground to safety.
And the results were in after a few minutes. Nanako 1st, Teddie 2nd, Yosuke 3rd, Chie 4th, Naoto 5th, Kanji 6th, Rise 7th, Yu 8th, and Yukiko last. The unconscious Namatame was eventually brought to the party.
Afterwards, Rise guided everyone to the exit. Although Nanako was still extremely chipper (thanks to her persona giving her an enormous speed buff), everyone else was exhausted. As the exit TVs were opened, Nanako leaped through into Junes, while the others groggily slumped through. As they walked out, Rise couldn't take any more, and slumped onto the floor.
Nanako was concerned for Rise, "Oh. She's fallen over. Can I use my persona to heal her?"
Yu decided to tell the bad news. "Sorry, but we can't use our personas outside that world. But don't worry, it looks like she's just asleep from all that... Runninngh..." Yu then collapsed on top of her. Yukiko quickly added herself to the pile, as they were all nigh on finished.
Chie did not approve of the three sleeping. "Aw, come on you wimps. We're all really... *yawn* tired... But that's no reason to crash here, especially not on top of each-other."
"Exactly! It wasn't even all that far." Nanako, with a brand new persona and a remarkably high speed stat, was very eager to side with Chie.
Yosuke wasn't too happy with Yu, either. "Come on, you three! If nothing else, stop hogging all the girls, Yu-kun! Ugh, is if Namatame wasn't enough dead weight to carry..."
Yet, the trio refused to wake up. "Zzz... So warm..."
Chie has had enough! "Fine, I'll drag you out of here, wimps! However, I won't forgive this, you hear me?"
Rise was much happier staying there (well, her shadow was, at least!). "No... I'd rather... Stay here, thank you..."
"Yu-kun is on top of you! Ugh, fine. I guess I'll have to carry you three with force!" Chie grabbed Yukiko by the waist. Yukiko tried to hold on to Yu, but was dragged away. Yosuke then picked up Yu, who was no longer on top of Rise thanks to Yukiko. Naoto lifted Rise, while Kanji grabbed Namatame. Teddie was bearly able to stay awake himself, and slowly walked out without bearing any weight.
Nanako ran over to the Dojima residence. After all, she knew the way back from the few times that she was taken to Junes. She didn't know that Dojima was in hospital, so she rushed back. Yosuke decided to keep the bad news subtle. "Nanako-chan, wait up! Dojima-san's not in, so you'll need some keys. Here's Yu's set!"
"Thanks!" (Why is he never home...?)
"Oh, by the way, don't lock the door so Yu-kun can come in!"
"I won't. See you later!"
Yosuke then set Yu down, as he was beginning to wake up. He decided to go to the hospital, so he could tell Dojima the good news.
In the hospital, Dojima was laid down in bed. Yu found his room, and walked in.
"I-Is Nanako OK?!"
Yu sighed. "Yes, at our expense. She made us sprint at least a marathon and I am absolutely knackered..."
Dojima laughed. "It looks like someone needs to hit the gym! Anyway, where is she?"
Yu decided to troll Dojima, "She's back home, so get well quick!"
Dogima frowned at Yu. "What do you think I'm doing? At least let me see her at some point."
"That will probably be at her discretion, but I'll pass the message."
"Thanks..." The sarcasm leaking from Dojima's voice was not well hidden. Yu laughed in response, and walked back home.
The end