What I wonder is if whether a fragment a needless develops is determined by the desires of said person.
Because if the big guy is indeed Gido, then he gained a fragment that allowed him go back to his young self. In fact, how many times we have seen him making claims against his age, such as when during the A.P. flashback he made a comment about his hairline and worrying he might go bald.
And now he's young again, and boosted up by the Eden Seed.
Likewise, Cruz always had a desire to protect those who are important around him.
And way back during the battle at Iron Mountain, Setsuna said to Eve:
With the exception of the manmade fragments (Zero & Doppelganger), it's apparent that the human brain of a needless crafts the fragment based on the person's longings.
And in Gido's case, his is being afraid of growing old!
Just some random thoughts of mine I thought you would find interesting, so I throw them here so we can discuss
