Ｈｅａｄｃａｎｏｎ--Ｆｅａｒ
It isn't so difficult to determine what his true fear is.
There are many things that the argent knight is afraid of--failure being one of them. Isolation for another. Losing his friends and so forth. Yet all were chained together and sourced to the one essence of terror that would always be pertinent in his travels. The one thing that would always threaten to take him in the end or in a single moment.
The Darkness.
Again, obvious--but it was not like the fright he attained as a boy with a power that he could not even begin to fathom. Much of his heart entraps the lone essence that aids him in his quest, much like the half of luminous that is seated beside it. Where terror had been was instead replaced by respect--determination--and strength.
But the chance would always be there. The possibility of that festering basis taking him in the end, just as it did with so many. The most prominent being his former Master, Xehanort. So alike they were--even down to their own little world. They walked the same path once. Tread down the hallowed ground that belonged to the denizens of the Light, yet remained in the dark.
A mercy more than an actual gift.
Unlike the Light, Darkness devours and consumes. It only engulfs and eradicates life--nothing more and nothing less. To have something that foul resting within your heart... well it makes him wonder. Wonder of just how long he can keep it at bay. A day may come where his heart may give in, or where the Light will no longer abide by his Darkness, or perhaps that even he will turn of his own accord.
That fear will always be there.
For as long as he lives.