Apologies on the delay, the original two moderators that were looking over your app have recently gone missing or were too swamped with real life issues. Now, let's break apart this app.

• Please Center your headers. (The name, THE INFO, THE NINJA, THE BACKGROUND, etc.) It's the way that applications are meant to be written out.
  
• Age would just be "17", regardless of whether or not he knows this. That information can be placed in the history.
  
• Make your Appearance into a single paragraph, rather than line-breaking after every sentence, or half sentence. On that note, greatly expand on your appearance. Key things such as "His posture varies based on personality" could easily be adapted on to explain how each personality influences him. Should end up being a very well written paragraph. One that runs smoothly and everything. (Not just He, he, his, him, he at the start of each sentence.)
  
• Same with personalities, although, this will need far greater depth. First, please explain the type of personality illness your character has. Is it Schizophrenia or Dissociative Identity Disorder? I assume the latter, although it's never really explained. Just because your character doesn't know, doesn't mean you don't. Would be nice to know exactly what kind of illness he has. If necessary, use google. Second: since you wish to have separate personalities, you'll need to go in depth on each personality. Each personality should be as long as a regular personality, and equally in depth. You have 5 personalities, you're expected to detail each five. Not just give a rough explanation for each one. Thus, 2 paragraphs for each one, detailing their interests, likes, and everything else one would fit into a personality. It's a lot, but this should be expected when creating such a complex character.
  
• Origin should be a country. Again, just because your character doesn't know, doesn't mean you don't.
  
• Affiliation should be N/A or something specific. This is an application, not a place to make punch-lines.
  
• You lack elemental affinities. You don't have to use any of them, but you may still have them, so that training for them later isn't a time consuming task. You may have up to 2, and as I said, you don't need to actually have jutsu for them now, or ever for that matter.
  
• Each description in the combat style should be expanded on more, to be a decent paragraph each. Here's an excerpt from the Creations Guide to help you with making your combat style:

  Combat Style wrote:

  How does your character like to fight? Hit and run tactics, a fearless tank on the battlefield or do you lurk in the shadows and kill silently. There are many different tactics and here is where you can write a brief description of the combat style in which encapsulates your character. This in some regards can be seen as a characters 'Combat Nindō'. Include such things as your strengths/weaknesses, the range in which your character likes to fight, any martial or other styles they have learn't, and your 'trump card' or otherwise known as 'Signature Jutsu'.

• Your history has some inconsistencies and issues as well.. Let's break it down.

  Quote :

  Even from the beginning, Gavin never had any real family. His family was a part of the Kaguya clan, an aggressive clan that used their powerful bone manipulation to take over other villages. His mother was in one of those villages, and his father raped her, just like any other woman. She put up a lot of struggle and tried to escape a lot, so after Gavin was born, they killed his mother.

  So, who is "they", and why did "they" kill your character's mother? This isn't explained even in the slightest anywhere. Please elaborate further.
  

  Quote :

  When he was about five, his clan finally went too far. They tried to attack a village far too big for them, and finally got defeated. None of those attacking survived, they fought to the end no matter what. Right after that, the other village invaded and wiped the rest of them out, they didn't want the Kaguyas to come back. However, they saw the helpless child, and unlike the Kaguyas, they felt pity for him.

  You jump straight to him being five.. but who was taking care of him between the ages of 0 and 4? That's five years completely left out. Did your character grow up in an orphanage? With his father? What? On another note, you say that the entire Kaguya clan was wiped out. Something that is not in accordance to the site, and definitely not with other members of the Kaguya clan. Do detail that it was only your 'section' of the Kaguya clan to be wiped out. Not all of them except for you. It's a site clan, not a personal clan. You can't modify the history to your liking if it's not your clan.
  

  Quote :

  They brought Gavin back to their village, but they didn't raise him. They were still afraid of him and his kekkei genkai, so he had to live off of their scraps. At about the age of seven, he began idolizing a ninja from the village. His idol's name was Gavin, and he was just a teenager. But he was a happy, energetic ninja that actually talked to him. This is where Gavin came to call him self that name, and why that personality acts that way.

  Again, where did your character live? With these people, or running the street? You say he ate scraps, but fail to detail what he actually did.
  
  The rest is focused around your character's attaining of personalities.. but I don't quite understand it. Essentially, your character NEVER went to the ninja Academy (thus, how can he even use Academy jutsu?) and never actually graduated as a Genin; nor does he seem to pose any real threat to.. well.. anyone. I fail to see how exactly your character is a Missing Ninja at all; when he committed no crime and didn't even abandon a hidden village. Any villager can just leave Kumo or Konoha; but when a soldier defects, that's different. It doesn't make matters any better that you never mentioned your character ever being part of a hidden village. So again, I ask you, how is he a missing ninja when he doesn't fit any of the regulations to actually be one? Either way, personality wise, though it is clever how your character gained these 'personalities', I fail to see HOW he actually got them. By this I mean, how did a completely different personality just randomly form in your character's head? Was it trauma that made his mind weak, or was it just a generic mental disease he had since birth? Also note, that just because you meet someone, that doesn't mean you immediately.. 'steal' their personality. Then again, I don't know what kind of illness he has, or how it functions.
  
  Basically; fix up your history so it makes a bit more sense with the ninja world, and explains why your character would be labeled a missing ninja, or a ninja at all. Also note; that you don't explain much of your character's teenage years. He's 17, explain more on his life as a teenager. Did he run around and steal? Did he learn Academy jutsu from other people? AS of right now, the history is quite a bit confusing.