Must. At least. TRY. To. Write.
The thin, murky line between ocher sea and violet sky has been unchanging for hours. He lost all feeling in his butt about twenty minutes ago.
Experience has taught him that there is only one way to keep entertained on long stretches of night like this. Books cannot keep his eyes to the seas like they need to be. That, and he has thumbed through every page in the library by now. Zoro's mindless training diagrams and Usopp's do-it-yourself directions can only entertain a man for so long. The flit of a flame from his lighter has long since lost its appeal. And, with Luffy's exhausting adventures, it's a rare occasion indeed when someone sacrifices precious sleep to pay the poor sap on watch a visit.
The mind, however, is endless. The mind shows him the crooked, beckoning fingers of effervescent spirits—tantalizing dreams of someone he cannot hold or the feel of his toes dipping into waters he cannot see. The play of light against orange or black or blue hair and the wafting scent of a meal he cannot name. He sees familiar smiles of yellowing teeth and eyes he knows better than his own with glittering ambitions.
He doesn't remember where his dreams and desires end, and where everyone else's begin.
Before, when it was only he, only him leaning over the railing of a rocking fish-ship with the stink of raw catch and his cigarettes in his nose, his mind was so much less. He closed his eyes and pretended the roll of waves under his shoes and the boat's planks was the brine of All Blue. It was only one dream there, with a few snatches of a woman's curves thrown in.
Now, it is a crown only in name and a sword thrust high into the air. It is as much feet to the dirt as ink on paper. It is the recognition of self and the dissolution of every hollow void. It is an answer to death until it is time, a song for worthy ears, and a home to carry them across the seas. Theirs is as much All Blue as the every fish swimming in the collecting water.
His mind is endless because they made it so. He is done adventuring it, for now, when he finally sees where the horizon stops and starts.