"Iruka Sensei, thanks for the extra help." Naruto was exhausted after a few hours of practicing the Clone Jutsu, a few decent ones came out but far from perfect.
"Any time Naruto, you're improving - if slowly, but I can see your determination. Hey, are you okay?" Naruto was having trouble standing and almost fell over but was caught by Iruka.
The following day, Naruto showed up late to class. He seemed out of it, still exhausted. Perhaps he was sick? He didn't even bother fighting back when the students teased him or when Iruka reprimanded him. The teacher called out: "Because Naruto came late to the first part of the lesson, we are going to practice the Clone Jutsu."
After the students finished their complaining, they walked down to the front of the classroom to form a line. Naruto had a blank look on his face and would be last. When it came time for him to perform, he just stood there as if he didn't hear the instructions. After snapping out of it, he walked up to Iruka and made the required handsigns. Nothing happened, not even a dead looking clone – there was no reaction. With that, Naruto swayed side to side and eventually collapsed to the floor.
Later that day, Iruka was in the waiting room at the hospital. For reasons unknown, the Third Hokage himself oversaw Naruto's visit and would let nobody else in – not even the doctors. The Third came out after what seemed like an eternity, he quickly closed the door behind him and gave out a sigh of relief.
Iruka approached the room. "Hokage Sama, will Naruto be alright? I should not have trained him so hard."
"Naruto will be just fine, it was just Chakra exhaustion. You're training wasn't the sole cause of this so don't worry." The old man pulled his pipe out blowing a ring of smoke.
"Then what else caused this? Surely it wasn't…. you know." Iruka visioned the frightening power of the fox in his head and gulped.
"No, that's not it either. Since the child was born, I have taken measures to keep the identity as safe as possible." He made a long drawn out sigh. "Some might call my measures extreme, but I believe it to be better this way. The day has come to begin dropping some safeguards around Naruto. You may go in now, alone. But be warned, you may not like what you find."
Iruka could not begin to imagine what this warning meant, all he could do was speculate as he entered the room. Closing the door behind him, he called out: "Naruto?"
On a lone bed was a figure completely covered by a sheet. As Iruka called out, the figure turned itself away and scrunched into a ball underneath the cloth. Whatever was going on, Naruto did not want to be seen.
"Naruto, it's me Iruka. Nobody else is here; you don't need to hide from me." The figure turned over to face him. As he walked over, a hand came from the side and pulled the sheet away. There, in the bed was a girl! Only her face was visible, she had chin length blue hair and amber colored eyes. Her facial structure was completely different.
"Is that Naruto?" He thought to himself. "She is beautiful."
"Iruka Sensei." She called out. "I'm sorry."
"What are you sorry for? Everything will be okay." He said as he tried to comfort the sad look in her eyes.
"I'm sorry for hiding it from you, from everyone." Her eyes swelled up and she covered her face again.
"Really, it's okay. I'm just not entirely sure why…" He took a seat on a nearby chair.
"The old man said it was to protect me, but why I don't know. He said that as I got older the jutsu would no longer have any effect. I guess it was that time…." The voice was muffled under the cloth.
"Tell you what Naruto, when you get out of here the first thing we will do is get Ramen! My treat." As he finished what he was saying the sheet was instantly thrown off, underneath was a smile.
"Iruka Sensei, don't call me that anymore. My real name is Naruko." The two stared at one another, as if they had had just met.
"Alright Naruko, that will be an easy thing to adjust to. Sorting out the Academy will be a bit trickier. I'll discuss it with the Hokage." With that he went to leave the room. "I'll see you soon, Naruko."
Note: If you want a better idea of what Naruko looks like, look up the character Konan. I modelled Naruko after her younger self. I did not want to be like everyone else and just use the sexy jutsu version. If we ever get to a point where Konan is shown, I will alter her appearance. And as for the blue hair, I will explain that in time.