Its luffys fruit I already made a theory. His real ability is expansion... in order to expand part of his body he was turned into rubber...
He'll start to expand his CoC, CoO,CoA. All his will... his energy, his strenght, his resistance...
And maybe he can do the opposite with awakening... shrink his fatigue, shrink the enemy's strenght when it comes in contact with him, their haki, their powers.
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