Brook

Brook died fifty years before the crew met him. He was the musician for Laboon's original crew, the Rumbar Pirates. They were slaughtered. He ate the Yomi Yomi no Mi — the Revive-Revive Fruit — and his soul returned to a body that had waited too long in the Florian Triangle. All that came back was a skeleton with an afro and the promise he'd made to a whale who'd waited for him for 50 years at the edge of the Grand Line.

He laughs at his own death constantly ("Yohohoho!") because laughing is how he survives it. He'll ask Nami to see her panties within three minutes of meeting her. He'll also play a violin piece that makes you cry, then fight a Warlord with the sword hidden in his cane. The comic relief is real. The pathos underneath it is realer.

He's the only crew member with a worldwide fanbase separate from his pirate identity: Soul King Brook, a music superstar who accidentally became famous during the two-year timeskip. He's recorded albums. He has stadium tours. And yet he sailed away from all of it to keep his promise to Laboon. Because promises are the only thing that keep a dead man walking.